CVE-2026-102556

HIGH 8.6

Published 2026-09-29 · Last modified 2026-10-19

A flaw was found in libsoup. When handling an incoming WebSocket Pong frame, SoupWebsocketConnection emitted the ::pong signal with a GByteArray pointer even though the signal is declared to pass a GBytes. Applications connecting a handler that follows the documented GBytes API can trigger heap corruption or a crash upon receiving a crafted Pong.

ELEVATED IMPACT

Severe if exploited (CVSS 8.6), but no known exploitation and low modeled probability. Patch on a normal cadence.

Exploitation likelihood

0.3%chance of exploitation in 30 days · 19th percentile

○ In CISA KEV ○ Public exploit / PoC

Impact if exploited

8.6CVSS 3.1 · HIGH

ConfidentialityLow
IntegrityLow
AvailabilityHigh

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 & exploit code

github-search Search GitHub for public PoC repos

Test against your own equipment

curl -s https://vulnpedia.com/cve/CVE-2026-102556/poc.jsonMachine-readable PoC index for this CVE (for automation).

Listed for defensive triage, patch verification, and authorized testing on systems you own. Machine-readable: /cve/CVE-2026-102556/poc.json

Affected

Vendors Red Hat Gnome Redhat

Products Red Hat Enterprise Linux 10 Red Hat Enterprise Linux 8 Red Hat Enterprise Linux 9 Red Hat Enterprise Linux 6 Red Hat Enterprise Linux 7 Libsoup Enterprise Linux

Weakness (CWE)

CWE-843: Access of Resource Using Incompatible Type ('Type Confusion')

CVSS vector

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

Known Affected Software Configurations

Vendor	Product	Version range
Gnome	Libsoup	< 3.7.3
Redhat	Enterprise Linux	7.0
Redhat	Enterprise Linux	8.0
Redhat	Enterprise Linux	9.0
Redhat	Enterprise Linux	10.0

All CVSS metrics

HIGH 8.6 v3.1 · CNA Primary
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H
HIGH 8.6 v3.1 · NVD Secondary
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H

References

Patches & mitigations

https://access.redhat.com/security/cve/CVE-2026-102556 vdb-entryx_refsource_REDHATMitigationVendor Advisory

Advisories

https://access.redhat.com/errata/RHSA-2026:83384 vendor-advisoryx_refsource_REDHATVendor Advisory
https://access.redhat.com/errata/RHSA-2026:83618 vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:84586 vendor-advisoryx_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2543229 issue-trackingx_refsource_REDHATIssue TrackingVendor Advisory

Sources: NVD · CVE.org · EPSS