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CVE-2026-92707

MEDIUM 5.3

Published 2026-10-15 · Last modified 2026-10-15

MessagePack for C# is a MessagePack serializer for C#. Prior to 2.5.303 and 3.1.9, deserializing attacker-controlled MessagePack data as System.Object through PrimitiveObjectFormatter can cause excessive memory allocation. The formatter allocates an object[] from each declared array length before the configured object-graph depth limit rejects the input, while nested array headers can reuse the same trailing unread bytes to satisfy per-header length validation. A comparatively small payload can therefore keep many large arrays alive at once. When an attacker can submit such data repeatedly, the allocations can cause severe managed-heap pressure, excessive garbage collection, process termination, or loss of service. Exposure requires an application to deserialize untrusted data through the affected formatter path and permit repeated attacker-controlled submissions, such as a reachable ASP.NET Core SignalR hub method with an object parameter and AddMessagePackProtocol() enabled. This issue is fixed in versions 2.5.303 and 3.1.9.

NO EXPLOITATION SIGNALS

No known exploitation, public exploit, or elevated probability at this time. Track for changes.

Exploitation likelihood

0.7%chance of exploitation in 30 days · 52nd percentile

○ In CISA KEV ○ Catalogued PoC

Impact if exploited

5.3CVSS 3.1 · MEDIUM

  • ConfidentialityNone
  • IntegrityNone
  • AvailabilityLow

What an attacker needs

  • ✓Access: Reachable over the network — no local access needed
  • ✓Privileges: No account or privileges required
  • ✓User interaction: No user interaction needed
  • ✓Complexity: No special conditions — reliably repeatable

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept

No public PoC is currently catalogued.

Search for new PoCs

Search GitHub now — results may be empty or unverified.

Tracked sources are checked daily for recent CVEs, including PoCs published after the original disclosure. A later release appears after a tracked source lists it and a refresh succeeds.

Data snapshot:

Affected

Vendors Messagepack Csharp

Products Messagepack Csharp

Weakness (CWE)

  • CWE-1325: : Improperly Controlled Sequential Memory Allocation

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

References and research data (JSON)

Packages and version ranges

Each advisory describes its own package and affected ranges. A boundary applies to that range; it is not a universal upgrade recommendation.

  • MessagePack NuGet

    pkg:nuget/MessagePack

    ECOSYSTEM range
    • All earlier versions (introduced 0)
    • Fixed boundary (excluded): 2.5.303
    122 explicitly listed affected versions

    0.1.0-beta, 0.2.0-beta, 0.2.1-beta, 0.2.2-beta, 0.2.3-beta, 0.3.0-beta, 0.4.0, 0.4.1, 0.4.2, 0.5.0, 0.6.0, 0.6.1, 0.7.0, 0.7.2, 0.8.0, 0.8.1, 0.8.2, 0.8.3, 0.8.4, 0.8.5, 1.0.0, 1.0.1, 1.0.2, 1.0.3, 1.1.0, 1.1.1, 1.1.1.1, 1.1.2, 1.2.0, 1.2.0.1, 1.2.0.2, 1.2.1, 1.2.2, 1.2.3, 1.3.0, 1.3.1, 1.3.1.1, 1.3.2, 1.3.3, 1.4.0, 1.4.1, 1.4.2, 1.4.3, 1.4.4, 1.5.0, 1.5.0.1, 1.5.0.2, 1.5.1, 1.6.0, 1.6.0.1, 1.6.0.2, 1.6.0.3, 1.6.1, 1.6.1.1, 1.6.1.2, 1.6.2, 1.7.0, 1.7.1, 1.7.2, 1.7.3, 1.7.3.1, 1.7.3.2, 1.7.3.3, 1.7.3.4, 1.7.3.7, 1.8.71-beta, 1.8.74, 1.8.80, 1.9.11, 1.9.3, 1.9.3-g129239b107, 2.0.107-alpha, 2.0.108-alpha, 2.0.110-alpha, 2.0.110-alpha-g1e44a9106f, 2.0.119-beta, 2.0.123-beta, 2.0.171-beta, 2.0.204-beta, 2.0.221-beta, 2.0.231-rc, 2.0.270-rc, 2.0.299-rc, 2.0.323, 2.0.335, 2.1.115, 2.1.143, 2.1.152, 2.1.165, 2.1.194, 2.1.80, 2.1.90, 2.2.113, 2.2.36-alpha, 2.2.44-rc, 2.2.60, 2.2.85, 2.3.112, 2.3.58-alpha, 2.3.73-alpha, 2.3.75, 2.3.85, 2.4.14-alpha, 2.4.23-alpha, 2.4.35, 2.4.59, 2.5.103, 2.5.108, 2.5.124, 2.5.129, 2.5.140, 2.5.168, 2.5.171, 2.5.172, 2.5.187, 2.5.192, 2.5.198, 2.5.205, 2.5.301, 2.5.302, 2.5.64-alpha, 2.5.94

    Additional upstream package constraints
    {
  "database": {
    "source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-qhrr-8q5h-9q3h/GHSA-qhrr-8q5h-9q3h.json"
  }
}
    GitHub Advisory Database · GHSA-qhrr-8q5h-9q3h · Updated 2026-10-15T18:45:11.655001723Z
  • MessagePack NuGet

    pkg:nuget/MessagePack

    ECOSYSTEM range
    • Introduced version (included): 3.0.0
    • Fixed boundary (excluded): 3.1.9
    17 explicitly listed affected versions

    3.0.111-alpha, 3.0.129-beta, 3.0.134-beta, 3.0.208-rc-0001, 3.0.3, 3.0.300, 3.0.308, 3.0.54-alpha, 3.1.0, 3.1.1, 3.1.2, 3.1.3, 3.1.4, 3.1.5, 3.1.6, 3.1.7, 3.1.8

    Additional upstream package constraints
    {
  "database": {
    "source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-qhrr-8q5h-9q3h/GHSA-qhrr-8q5h-9q3h.json"
  }
}
    GitHub Advisory Database · GHSA-qhrr-8q5h-9q3h · Updated 2026-10-15T18:45:11.655001723Z

Vendor product assessments

Showing 32 of 1306 vendor product statements; 1274 omitted. Read the full vendor advisory.

  • aspnetcore-runtime-8.0-0:8.0.32-1.el10_0.aarch64 as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_0?arch=aarch64

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Vendor guidance
    Red Hat · CVE-2026-92707 · Updated 2026-10-23T04:32:48+00:00
  • dotnet-host-debuginfo-0:9.0.21-1.el10_0.s390x as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_0?arch=s390x

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Vendor guidance
    Red Hat · CVE-2026-92707 · Updated 2026-10-23T04:32:48+00:00
  • dotnet-sdk-8.0-debuginfo-0:8.0.132-1.el10_0.ppc64le as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_0?arch=ppc64le

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Vendor guidance
    Red Hat · CVE-2026-92707 · Updated 2026-10-23T04:32:48+00:00
  • dotnet9.0-debugsource-0:9.0.122-1.el10_0.s390x as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_0?arch=s390x

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Vendor guidance
    Red Hat · CVE-2026-92707 · Updated 2026-10-23T04:32:48+00:00
  • dotnet-apphost-pack-10.0-debuginfo-0:10.0.13-1.el10_2.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_2?arch=aarch64

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Vendor guidance
    Red Hat · CVE-2026-92707 · Updated 2026-10-23T04:32:48+00:00
  • dotnet-hostfxr-9.0-0:9.0.21-1.el10_2.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_2?arch=s390x

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Vendor guidance
    Red Hat · CVE-2026-92707 · Updated 2026-10-23T04:32:48+00:00
  • dotnet-sdk-10.0-debuginfo-0:10.0.113-1.el10_2.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_2?arch=ppc64le

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Vendor guidance
    Red Hat · CVE-2026-92707 · Updated 2026-10-23T04:32:48+00:00
  • dotnet-targeting-pack-9.0-0:9.0.21-1.el10_2.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_2?arch=aarch64

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Vendor guidance
    Red Hat · CVE-2026-92707 · Updated 2026-10-23T04:32:48+00:00
  • aspnetcore-runtime-9.0-0:9.0.21-1.el8_10.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 8) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_10?arch=x86_64

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Vendor guidance
    Red Hat · CVE-2026-92707 · Updated 2026-10-23T04:32:48+00:00
  • dotnet-apphost-pack-9.0-0:9.0.21-1.el8_10.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 8) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_10?arch=ppc64le

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Vendor guidance
    Red Hat · CVE-2026-92707 · Updated 2026-10-23T04:32:48+00:00
  • dotnet-runtime-9.0-0:9.0.21-1.el8_10.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 8) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_10?arch=aarch64

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Vendor guidance
    Red Hat · CVE-2026-92707 · Updated 2026-10-23T04:32:48+00:00
  • dotnet-sdk-aot-10.0-debuginfo-0:10.0.113-1.el8_10.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 8) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_10?arch=x86_64

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Vendor guidance
    Red Hat · CVE-2026-92707 · Updated 2026-10-23T04:32:48+00:00
  • dotnet10.0-debugsource-0:10.0.113-1.el8_10.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 8) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_10?arch=aarch64

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Vendor guidance
    Red Hat · CVE-2026-92707 · Updated 2026-10-23T04:32:48+00:00
  • dotnet-host-0:8.0.32-1.el9_4.aarch64 as a component of Red Hat Enterprise Linux AppStream E4S (v.9.4) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_4?arch=aarch64

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Vendor guidance
    Red Hat · CVE-2026-92707 · Updated 2026-10-23T04:32:48+00:00
  • dotnet-templates-8.0-0:8.0.132-1.el9_4.x86_64 as a component of Red Hat Enterprise Linux AppStream E4S (v.9.4) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_4?arch=x86_64

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Vendor guidance
    Red Hat · CVE-2026-92707 · Updated 2026-10-23T04:32:48+00:00
  • dotnet-runtime-8.0-debuginfo-0:8.0.32-1.el9_6.ppc64le as a component of Red Hat Enterprise Linux AppStream EUS (v.9.6) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_6?arch=ppc64le

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Vendor guidance
    Red Hat · CVE-2026-92707 · Updated 2026-10-23T04:32:48+00:00
  • aspnetcore-runtime-9.0-0:9.0.21-1.el9_8.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_8?arch=s390x

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Vendor guidance
    Red Hat · CVE-2026-92707 · Updated 2026-10-23T04:32:48+00:00
  • dotnet-apphost-pack-9.0-debuginfo-0:9.0.21-1.el9_8.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_8?arch=aarch64

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Vendor guidance
    Red Hat · CVE-2026-92707 · Updated 2026-10-23T04:32:48+00:00
  • dotnet-runtime-8.0-0:8.0.32-1.el9_8.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 9) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_8?arch=x86_64

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Vendor guidance
    Red Hat · CVE-2026-92707 · Updated 2026-10-23T04:32:48+00:00
  • dotnet-sdk-9.0-debuginfo-0:9.0.122-1.el9_8.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_8?arch=s390x

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Vendor guidance
    Red Hat · CVE-2026-92707 · Updated 2026-10-23T04:32:48+00:00
  • dotnet10.0-0:10.0.113-1.el9_8.src as a component of Red Hat Enterprise Linux AppStream (v. 9) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_8?arch=src

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Vendor guidance
    Red Hat · CVE-2026-92707 · Updated 2026-10-23T04:32:48+00:00
  • dotnet-hostfxr-8.0-debuginfo-0:8.0.32-1.el10_0.x86_64 as a component of Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_0?arch=x86_64

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Vendor guidance
    Red Hat · CVE-2026-92707 · Updated 2026-10-23T04:32:48+00:00
  • dotnet-apphost-pack-9.0-debuginfo-0:9.0.21-1.el10_2.aarch64 as a component of Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_2?arch=aarch64

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Vendor guidance
    Red Hat · CVE-2026-92707 · Updated 2026-10-23T04:32:48+00:00
  • dotnet-sdk-8.0-source-built-artifacts-0:8.0.132-1.el10_2.x86_64 as a component of Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_2?arch=x86_64

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Vendor guidance
    Red Hat · CVE-2026-92707 · Updated 2026-10-23T04:32:48+00:00
  • dotnet-hostfxr-9.0-debuginfo-0:9.0.21-1.el8_10.ppc64le as a component of Red Hat Enterprise Linux CRB (v. 8) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_10?arch=ppc64le

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Vendor guidance
    Red Hat · CVE-2026-92707 · Updated 2026-10-23T04:32:48+00:00
  • dotnet10.0-debuginfo-0:10.0.113-1.el8_10.x86_64 as a component of Red Hat Enterprise Linux CRB (v. 8) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_10?arch=x86_64

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Vendor guidance
    Red Hat · CVE-2026-92707 · Updated 2026-10-23T04:32:48+00:00
  • dotnet8.0-debugsource-0:8.0.132-1.el9_6.s390x as a component of Red Hat CodeReady Linux Builder EUS (v.9.6) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_6?arch=s390x

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Vendor guidance
    Red Hat · CVE-2026-92707 · Updated 2026-10-23T04:32:48+00:00
  • dotnet-sdk-10.0-source-built-artifacts-0:10.0.113-1.el9_8.ppc64le as a component of Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_8?arch=ppc64le

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Vendor guidance
    Red Hat · CVE-2026-92707 · Updated 2026-10-23T04:32:48+00:00
  • dotnet9.0-debugsource-0:9.0.122-1.el9_8.x86_64 as a component of Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) · fixed

    Vendor assessment for this product only.

    pkg:rpm/redhat/[email protected]_8?arch=x86_64

    • vendor fix: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Vendor guidance
    Red Hat · CVE-2026-92707 · Updated 2026-10-23T04:32:48+00:00
  • dotnet10.0.src as a component of Red Hat Hardened Images · known not affected

    Vendor assessment for this product only.

    Reason: component not present

    pkg:rpm/redhat/[email protected]?arch=src

    Red Hat · CVE-2026-92707 · Updated 2026-10-23T04:32:48+00:00
  • dotnet8.0.src as a component of Red Hat Hardened Images · known not affected

    Vendor assessment for this product only.

    Reason: component not present

    pkg:rpm/redhat/[email protected]?arch=src

    Red Hat · CVE-2026-92707 · Updated 2026-10-23T04:32:48+00:00
  • dotnet9.0.src as a component of Red Hat Hardened Images · known not affected

    Vendor assessment for this product only.

    Reason: component not present

    pkg:rpm/redhat/[email protected]?arch=src

    Red Hat · CVE-2026-92707 · Updated 2026-10-23T04:32:48+00:00

All CVSS metrics

  • MEDIUM 5.3 v3.1 · CNA Primary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
  • MEDIUM 5.3 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

References

Advisories

Technical & other

Sources: NVD · CVE.org · EPSS