CVE-2026-102558: 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
- 0.5% chance of exploitation in 30 days – higher than 48% 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
Configure a finite max-incoming-payload-size (do not set it to 0 or unlimited) on SoupWebsocketConnection to prevent the vulnerability. Additionally, restrict WebSocket exposure to trusted peers. These mitigations reduce the risk without requiring immediate patching. Check vendor advisories for any official fixes or updates.
Description
A heap buffer overflow vulnerability exists in libsoup2.4's SoupWebsocketConnection when the max-incoming-payload-size is set to unlimited (0). This flaw allows an attacker to cause the GByteArray length to wrap due to an attacker-controlled frame length, leading to heap corruption or denial of service.
References
- ubuntu.com/security/CVE-2026-102558 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-102558 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2543274 (opens in a new tab)
- gitlab.gnome.org/GNOME/libsoup/-/work_items/554 (opens in a new tab)
- access.redhat.com/security/cve/CVE-2026-102558 (opens in a new tab)