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CVE-2026-34475

MEDIUM 5.4 ALL-YEARS

Published 2026-03-27 · Last modified 2026-03-27 · mitre · NVD: Analyzed

Varnish Cache before 8.0.1 and Varnish Enterprise before 6.0.16r12, in certain unchecked req.url scenarios, mishandle URLs with a path of / for HTTP/1.1, potentially leading to cache poisoning or authentication bypass.

LIMITED SIGNALS

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

Exploitation likelihood

0.2%chance of exploitation in 30 days · 11th percentile

○ In CISA KEV○ Catalogued PoC◆ SSVC: exploitation none, automatable no

Impact if exploited

5.4CVSS 3.1 · MEDIUM · CNA

  • ConfidentialityLow
  • IntegrityLow
  • AvailabilityNone

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: Needs a race window or specific setup

✓ 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 weekly for the full archive, including PoCs published after the original disclosure. A later release appears after a tracked source lists it and a refresh succeeds.

Affected

Vendors Varnish Software Vinyl Cache

Products Varnish Cache Varnish Enterprise Vinyl Cache

Weakness (CWE)

  • CWE-180: Incorrect Behavior Order: Validate Before Canonicalize

CVSS vector

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

References and research data (JSON)

Vendor product assessments

  • varnish as a component of Red Hat Enterprise Linux 10 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/varnish

    • none available: Fix deferred
    Red Hat · CVE-2026-34475 · Updated 2026-06-30T11:42:42+00:00
  • varnish-devel as a component of Red Hat Enterprise Linux 10 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/varnish-devel

    • none available: Fix deferred
    Red Hat · CVE-2026-34475 · Updated 2026-06-30T11:42:42+00:00
  • varnish-docs as a component of Red Hat Enterprise Linux 10 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/varnish-docs

    • none available: Fix deferred
    Red Hat · CVE-2026-34475 · Updated 2026-06-30T11:42:42+00:00
  • varnish-modules.src as a component of Red Hat Enterprise Linux 10 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/varnish-modules?arch=src

    • none available: Fix deferred
    Red Hat · CVE-2026-34475 · Updated 2026-06-30T11:42:42+00:00
  • varnish.src as a component of Red Hat Enterprise Linux 10 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/varnish?arch=src

    • none available: Fix deferred
    Red Hat · CVE-2026-34475 · Updated 2026-06-30T11:42:42+00:00
  • varnish-devel (varnish:6) as a component of Red Hat Enterprise Linux 8 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/varnish-devel?rpmmod=varnish:6

    • none available: Fix deferred
    Red Hat · CVE-2026-34475 · Updated 2026-06-30T11:42:42+00:00
  • varnish-docs (varnish:6) as a component of Red Hat Enterprise Linux 8 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/varnish-docs?rpmmod=varnish:6

    • none available: Fix deferred
    Red Hat · CVE-2026-34475 · Updated 2026-06-30T11:42:42+00:00
  • varnish-modules.src (varnish:6) as a component of Red Hat Enterprise Linux 8 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/varnish-modules?arch=src&rpmmod=varnish:6

    • none available: Fix deferred
    Red Hat · CVE-2026-34475 · Updated 2026-06-30T11:42:42+00:00
  • varnish-modules (varnish:6) as a component of Red Hat Enterprise Linux 8 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/varnish-modules?rpmmod=varnish:6

    • none available: Fix deferred
    Red Hat · CVE-2026-34475 · Updated 2026-06-30T11:42:42+00:00
  • varnish.src (varnish:6) as a component of Red Hat Enterprise Linux 8 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/varnish?arch=src&rpmmod=varnish:6

    • none available: Fix deferred
    Red Hat · CVE-2026-34475 · Updated 2026-06-30T11:42:42+00:00
  • varnish (varnish:6) as a component of Red Hat Enterprise Linux 8 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/varnish?rpmmod=varnish:6

    • none available: Fix deferred
    Red Hat · CVE-2026-34475 · Updated 2026-06-30T11:42:42+00:00
  • varnish-modules.src as a component of Red Hat Enterprise Linux 9 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/varnish-modules?arch=src

    • none available: Fix deferred
    Red Hat · CVE-2026-34475 · Updated 2026-06-30T11:42:42+00:00
  • redhat-user-workloads/varnish-7-10-0 as a component of Red Hat Enterprise Linux 10 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:oci/rhel-10-0/varnish-7-10-0/varnish-7-10-0?repository_url=quay.io/redhat-user-workloads/osci-rhel-containers-tenant/rhel-10-0/varnish-7-10-0/varnish-7-10-0

    Red Hat · CVE-2026-34475 · Updated 2026-06-30T11:42:42+00:00
  • redhat-user-workloads/varnish-7-10-1 as a component of Red Hat Enterprise Linux 10 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:oci/rhel-10-1/varnish-7-10-1/varnish-7-10-1?repository_url=quay.io/redhat-user-workloads/osci-rhel-containers-tenant/rhel-10-1/varnish-7-10-1/varnish-7-10-1

    Red Hat · CVE-2026-34475 · Updated 2026-06-30T11:42:42+00:00
  • redhat-user-workloads/varnish-6-8-10 as a component of Red Hat Enterprise Linux 8 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:oci/varnish-6-8-10/varnish-6-8-10?repository_url=quay.io/redhat-user-workloads/osci-rhel-containers-tenant/varnish-6-8-10/varnish-6-8-10

    Red Hat · CVE-2026-34475 · Updated 2026-06-30T11:42:42+00:00
  • redhat-user-workloads/varnish-6-9-6 as a component of Red Hat Enterprise Linux 9 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:oci/rhel-9-6/varnish-6-9-6/varnish-6-9-6?repository_url=quay.io/redhat-user-workloads/osci-rhel-containers-tenant/rhel-9-6/varnish-6-9-6/varnish-6-9-6

    Red Hat · CVE-2026-34475 · Updated 2026-06-30T11:42:42+00:00
  • redhat-user-workloads/varnish-6-9-7 as a component of Red Hat Enterprise Linux 9 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:oci/rhel-9-7/varnish-6-9-7/varnish-6-9-7?repository_url=quay.io/redhat-user-workloads/osci-rhel-containers-tenant/rhel-9-7/varnish-6-9-7/varnish-6-9-7

    Red Hat · CVE-2026-34475 · Updated 2026-06-30T11:42:42+00:00
  • varnish as a component of Red Hat Enterprise Linux 9 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/varnish

    Red Hat · CVE-2026-34475 · Updated 2026-06-30T11:42:42+00:00
  • varnish-devel as a component of Red Hat Enterprise Linux 9 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/varnish-devel

    Red Hat · CVE-2026-34475 · Updated 2026-06-30T11:42:42+00:00
  • varnish-docs as a component of Red Hat Enterprise Linux 9 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/varnish-docs

    Red Hat · CVE-2026-34475 · Updated 2026-06-30T11:42:42+00:00
  • varnish.src as a component of Red Hat Enterprise Linux 9 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/varnish?arch=src

    Red Hat · CVE-2026-34475 · Updated 2026-06-30T11:42:42+00:00

Known Affected Software Configurations

VendorProductVersion range
Varnish SoftwareVarnish Enterprise≤ 6.0.15
Varnish SoftwareVarnish Enterprise6.0.16
Varnish SoftwareVarnish Enterprise6.0.16
Varnish SoftwareVarnish Enterprise6.0.16
Varnish SoftwareVarnish Enterprise6.0.16
Varnish SoftwareVarnish Enterprise6.0.16
Varnish SoftwareVarnish Enterprise6.0.16
Varnish SoftwareVarnish Enterprise6.0.16
Varnish SoftwareVarnish Enterprise6.0.16
Varnish SoftwareVarnish Enterprise6.0.16
Varnish SoftwareVarnish Enterprise6.0.16
Varnish SoftwareVarnish Enterprise6.0.16
Vinyl CacheVinyl Cache< 8.0.1

All CVSS metrics

  • MEDIUM 5.4 v3.1 · CNA Primary
    CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N
  • MEDIUM 5.4 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N
  • CRITICAL 9.8 v3.1 · NVD Primary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References

Patches & mitigations

Advisories

Technical & other

Sources: NVD · CVE.org · All sources and attribution · EPSS