CVE-2026-102556: Libsoup2.4 · A flaw was found in libsoup
Affects libsoup2.4Source GCVE Database
Not known to be exploited · CVSS 8.6 High.
Data as of 3 Nov 2026, 22:58 UTC
Thin evidence
One scorer or none| CNA (redhat) | CVSS 3.1 | 8.6 |
|---|
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 40% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:HExploitation evidence
Disclosed: evidence found.
CVE published 29 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 3 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10libsoup2.4pkg:deb/ubuntu/libsoup2.4?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10libsoup3pkg:deb/ubuntu/libsoup3?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlibsoup3pkg:deb/ubuntu/libsoup3?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu Pro 26.04 LTSlibsoup2.4pkg:deb/ubuntu/libsoup2.4?arch=source&distro=esm-apps/resoluteOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSlibsoup2.4pkg:deb/ubuntu/libsoup2.4?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSlibsoup3pkg:deb/ubuntu/libsoup3?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Avoid connecting custom handlers to the SoupWebsocketConnection::pong signal or avoid using WebSocket with untrusted peers. A fix is available in updated versions of libsoup2.4; users should upgrade to patched versions as provided by their vendor or distribution. If upgrading is not immediately possible, applying the mitigation by not connecting to the ::pong signal or restricting WebSocket connections to trusted peers reduces risk.
Description
A vulnerability in libsoup2.4 occurs when handling WebSocket Pong frames. The SoupWebsocketConnection emits a ::pong signal with a GByteArray pointer instead of the expected GBytes type, which can cause heap corruption or application crashes if an application connects a handler expecting the documented GBytes API and receives a crafted Pong frame.
References
- ubuntu.com/security/CVE-2026-102556 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-102556 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2543229 (opens in a new tab)
- gitlab.gnome.org/GNOME/libsoup/-/work_items/554 (opens in a new tab)
- access.redhat.com/security/cve/CVE-2026-102556 (opens in a new tab)