Libsoup3: The fix for CVE-2026-0716 (commit 6ff7ef0, libsoup 3.6.6) placed the integer overflow guard inside the if
Affects libsoup3Source GCVE Database
Mentioned vulnerabilities
Not known to be exploited · CVSS 4.8 Medium.
Data as of 3 Nov 2026, 23:14 UTC
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:LExploitation evidence
Disclosed: evidence found.
CVE published 14 Jul 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 26.10libsoup3pkg: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 24.04 LTSlibsoup3pkg:deb/ubuntu/libsoup3?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu Pro 22.04 LTSlibsoup3pkg:deb/ubuntu/libsoup3?arch=source&distro=esm-apps/jammyOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
The fix for CVE-2026-0716 (commit 6ff7ef0, libsoup 3.6.6) placed the integer overflow guard inside the if (masked) block, leaving unmasked server-to-client frames unprotected. A malicious WebSocket server can send a crafted unmasked frame with a payload length near UINT64_MAX to trigger an OOB read in a libsoup-based client when max_incoming_payload_size is set to 0.
References
- ubuntu.com/security/CVE-2026-12478 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-12478 (opens in a new tab)
- access.redhat.com/security/cve/CVE-2026-12478 (opens in a new tab)
- access.redhat.com/security/cve/cve-2026-0716 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2489655 (opens in a new tab)
- gitlab.gnome.org/GNOME/libsoup/-/merge_requests/518 (opens in a new tab)