CVE-2026-99191: Linux kernel · calipso: keep BIG TCP payload_len in calipso_skbuff_setattr()
Affects Linux kernelSource GCVE Database
Not known to be exploited.
Data as of 29 Oct 2026, 22:45 UTC
Rated by Threat Radar · CVSS not yet scored by NVD
Thin evidence
One scorer or noneExploitation evidence
Disclosed: evidence found.
CVE published 28 Oct 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 29 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10linuxpkg:deb/ubuntu/linux?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-oraclepkg:deb/ubuntu/linux-oracle?arch=source&distro=stonkingOther 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
A fix is available that corrects the payload length calculation in calipso_skbuff_setattr(). Users should apply the updated Linux kernel versions that include this patch to ensure proper handling of large TCP payloads with CALIPSO options. No additional mitigation steps are indicated.
Description
CVE-2026-99191 is a vulnerability in the Linux kernel's calipso module affecting the handling of large TCP payload lengths in IPv6 packets. The issue arises from incorrect adjustment of the IPv6 payload length field when processing packets larger than the maximum IPv6 payload length (IPV6_MAXPLEN), causing potential misinterpretation of packet sizes by network subsystems relying on this value. This flaw was fixed by correctly setting the payload length based on the actual socket buffer length, ensuring accurate length representation for large TCP packets with CALIPSO options.
References
- ubuntu.com/security/CVE-2026-99191 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-99191 (opens in a new tab)
- git.kernel.org/stable/c/8070ed578b6b9134e045627fb745c887a806d46e (opens in a new tab)
- git.kernel.org/stable/c/8ee0e03663826a76507048d58466b29321a57656 (opens in a new tab)
- git.kernel.org/stable/c/1c9fcfca51e3c5cd46dd72a4da74d56eff183513 (opens in a new tab)