High severity · published Sep 29, 2026
CVE-2026-102556
Libsoup: libsoup: heap buffer overflow from websocket pong signal type confusion
8.6
CVSS
0.3%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
Low
Integrity
Low
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 20% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
RH
Red Hat Enterprise Linux 10 · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat Enterprise Linux 6 · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat Enterprise Linux 7 · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat Enterprise Linux 8 · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat Enterprise Linux 9 · Red Hat
All versions, or not specified · source: vendor
EL
Enterprise Linux · Redhat
7.0; 8.0; 9.0; 10.0 · source: NVD
LI
Libsoup · Gnome
before 3.7.3 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-102556
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-102556
vendor-advisory
https://access.redhat.com/errata/RHSA-2026:83384
vendor-advisory
https://access.redhat.com/errata/RHSA-2026:83618
vendor-advisory
https://access.redhat.com/errata/RHSA-2026:84586
vdb-entry
https://access.redhat.com/security/cve/CVE-2026-102556
issue-tracking
https://bugzilla.redhat.com/show_bug.cgi?id=2543229
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