VulnerabilityPublished 28 Oct 2026

CVE-2026-99191: Linux kernel · calipso: keep BIG TCP payload_len in calipso_skbuff_setattr()

Source GCVE Database

Authoritative record:CVE-2026-99191

Not known to be exploited · fixed in 8070ed578b6b9134e045627fb745c887a806d46e : update Linux kernel when convenient.

Data as of 28 Oct 2026, 13:46 UTC

Severity

Medium

Rated Medium by Threat Radar's AI analysis · CVSS not yet scored by NVD

Patch: Available – fixed in 8070ed578b6b9134e045627fb745c887a806d46e, 8ee0e03663826a76507048d58466b29321a57656, 1c9fcfca51e3c5cd46dd72a4da74d56eff183513

Exploitation evidence

Disclosed: evidence found.
CVE published 28 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

ghsa-4qqv-fgh9-mg86

What to do

Upgrade Linux kernel to 8070ed578b6b9134e045627fb745c887a806d46e, 8ee0e03663826a76507048d58466b29321a57656 or 1c9fcfca51e3c5cd46dd72a4da74d56eff183513.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 81fbc812132cbc72a0f933b19bfd3a829bd946e4, < 8070ed578b6b9134e045627fb745c887a806d46e	Fixed in 8070ed578b6b9134e045627fb745c887a806d46e
LinuxLinux	Affected ≥ 81fbc812132cbc72a0f933b19bfd3a829bd946e4, < 8ee0e03663826a76507048d58466b29321a57656	Fixed in 8ee0e03663826a76507048d58466b29321a57656
LinuxLinux	Affected ≥ 81fbc812132cbc72a0f933b19bfd3a829bd946e4, < 1c9fcfca51e3c5cd46dd72a4da74d56eff183513	Fixed in 1c9fcfca51e3c5cd46dd72a4da74d56eff183513
LinuxLinux	Affected =5.19	Fixed in–

AI-suggested

A fix has been implemented in the Linux kernel to correctly handle large TCP payload lengths in calipso_skbuff_setattr(). Users should apply the official kernel update containing this fix. No additional mitigation actions are indicated.

Description

A vulnerability in the Linux kernel's calipso_skbuff_setattr() function mishandles large TCP payload lengths in IPv6 packets with CALIPSO options. This causes incorrect payload_len values when packets exceed the IPV6_MAXPLEN limit, potentially affecting network packet processing components such as nf_tables, conntrack, and sch_cake. The issue has been fixed by correctly setting payload_len based on the actual skb length, ensuring proper handling of large TCP packets with CALIPSO labels.

References

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