CVE-2026-102557

Libsoup: libsoup: heap buffer overflow during websocket message reassembly

Published Sep 29, 2026 CVSS 3.1 · 8.6 High EPSS < 1% KEV · Not listed
Description
A flaw was found in libsoup. When reassembling fragmented WebSocket messages into a GByteArray, libsoup did not adequately cap total message size against the limits of the underlying buffer type. A remote peer could send fragments that caused size truncation while the implementation still used the full length, leading to heap corruption or a crash.

Remediation

Vendor Workaround

To mitigate this set a conservative max-total-incoming-message-size / incoming payload limits where the API allows, and do not accept WebSocket connections from untrusted peers.

Tracking

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Advisories

Source ID Title
Ubuntu USN Ubuntu USN USN-8975-1 libsoup vulnerabilities
History
Type Values Removed Values Added
CPEs cpe:/o:redhat:enterprise_linux:10.3
References
Type Values Removed Values Added
CPEs cpe:/o:redhat:enterprise_linux:6 cpe:/o:redhat:rhel_els:6
Type Values Removed Values Added
CPEs cpe:/a:redhat:rhel_aus:8.6::appstream
cpe:/a:redhat:rhel_eus_long_life:8.6::appstream
cpe:/o:redhat:rhel_aus:8.6::baseos
cpe:/o:redhat:rhel_eus_long_life:8.6::baseos
References
Type Values Removed Values Added
First Time appeared Redhat enterprise Linux Eus
CPEs cpe:/o:redhat:enterprise_linux_eus:10.0
Vendors & Products Redhat enterprise Linux Eus
References
Type Values Removed Values Added
First Time appeared Redhat rhel Els
Redhat rhel Eus
CPEs cpe:/o:redhat:enterprise_linux:7 cpe:/a:redhat:rhel_eus:9.6::appstream
cpe:/o:redhat:rhel_els:7
Vendors & Products Redhat rhel Els
Redhat rhel Eus
References
Type Values Removed Values Added
First Time appeared Redhat rhel Tus
CPEs cpe:/a:redhat:rhel_e4s:8.8::appstream
cpe:/a:redhat:rhel_tus:8.8::appstream
cpe:/o:redhat:rhel_e4s:8.8::baseos
cpe:/o:redhat:rhel_tus:8.8::baseos
Vendors & Products Redhat rhel Tus
References
Type Values Removed Values Added
First Time appeared Redhat rhel E4s
CPEs cpe:/a:redhat:rhel_e4s:9.2::appstream
cpe:/a:redhat:rhel_e4s:9.4::appstream
Vendors & Products Redhat rhel E4s
References
Type Values Removed Values Added
First Time appeared Redhat rhel Aus
Redhat rhel Eus Long Life
CPEs cpe:/a:redhat:rhel_aus:8.4::appstream
cpe:/a:redhat:rhel_eus_long_life:8.4::appstream
cpe:/o:redhat:rhel_aus:8.4::baseos
cpe:/o:redhat:rhel_eus_long_life:8.4::baseos
Vendors & Products Redhat rhel Aus
Redhat rhel Eus Long Life
References
Type Values Removed Values Added
CPEs cpe:/o:redhat:enterprise_linux:8 cpe:/a:redhat:enterprise_linux:8::appstream
cpe:/o:redhat:enterprise_linux:8::baseos
References
Type Values Removed Values Added
CPEs cpe:/o:redhat:enterprise_linux:10 cpe:/o:redhat:enterprise_linux:10.2
References
Type Values Removed Values Added
First Time appeared Gnome
Gnome libsoup
CPEs cpe:2.3:a:gnome:libsoup:*:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux:10.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:*
Vendors & Products Gnome
Gnome libsoup
Type Values Removed Values Added
CPEs cpe:/o:redhat:enterprise_linux:9 cpe:/a:redhat:enterprise_linux:9::appstream
References
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Libsoup
Libsoup libsoup
Vendors & Products Libsoup
Libsoup libsoup
Type Values Removed Values Added
Description A flaw was found in libsoup. When reassembling fragmented WebSocket messages into a GByteArray, libsoup did not adequately cap total message size against the limits of the underlying buffer type. A remote peer could send fragments that caused size truncation while the implementation still used the full length, leading to heap corruption or a crash.
Title Libsoup: libsoup: heap buffer overflow during websocket message reassembly
First Time appeared Redhat
Redhat enterprise Linux
Weaknesses CWE-125
CPEs cpe:/o:redhat:enterprise_linux:10
cpe:/o:redhat:enterprise_linux:6
cpe:/o:redhat:enterprise_linux:7
cpe:/o:redhat:enterprise_linux:8
cpe:/o:redhat:enterprise_linux:9
Vendors & Products Redhat
Redhat enterprise Linux
References
Metrics cvssV3_1

{'score': 8.6, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H'}