VulnerabilityPublished 26 Oct 2026

CVE-2026-99088: Linux kernel · net: openvswitch: validate transport header presence in set_ipv6_addr

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in b7b80d204abdc258006f9e17c92b363ab13bb599 : update Linux kernel when convenient.

Data as of 26 Oct 2026, 16:53 UTC

Severity

Low

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

Patch: Available – fixed in b7b80d204abdc258006f9e17c92b363ab13bb599, 2594795fd832f0253826d64ff8976b8ff5fbfe9f, 6774af7cd17be8f0d0f70de3a749d381b4f2e9da +2

Exploitation evidence

Disclosed: evidence found.
CVE published 26 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.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 3fdbd1ce11e5c0d7cafbe44c942c5cad61113d7b, < b7b80d204abdc258006f9e17c92b363ab13bb599	Fixed in b7b80d204abdc258006f9e17c92b363ab13bb599
LinuxLinux	Affected ≥ 3fdbd1ce11e5c0d7cafbe44c942c5cad61113d7b, < 2594795fd832f0253826d64ff8976b8ff5fbfe9f	Fixed in 2594795fd832f0253826d64ff8976b8ff5fbfe9f
LinuxLinux	Affected ≥ 3fdbd1ce11e5c0d7cafbe44c942c5cad61113d7b, < 6774af7cd17be8f0d0f70de3a749d381b4f2e9da	Fixed in 6774af7cd17be8f0d0f70de3a749d381b4f2e9da
LinuxLinux	Affected ≥ 3fdbd1ce11e5c0d7cafbe44c942c5cad61113d7b, < 6b8897ba0733f88f0360ea48a970f373f9142de0	Fixed in 6b8897ba0733f88f0360ea48a970f373f9142de0
LinuxLinux	Affected ≥ 3fdbd1ce11e5c0d7cafbe44c942c5cad61113d7b, < 3c6a4b11330fe424557538a98fca9f0a4c5bf313	Fixed in 3c6a4b11330fe424557538a98fca9f0a4c5bf313
LinuxLinux	Affected =3.8	Fixed in–

AI-suggested

A fix is available and has been applied in the Linux kernel. Users should update to the fixed kernel versions identified by the provided commit hashes. No additional mitigation is required as the issue only causes debug warnings and does not affect normal operation.

Description

A vulnerability in the Linux kernel's Open vSwitch component related to IPv6 address rewrite actions on IPv6 fragments has been fixed. The issue occurs because the transport header is not properly validated before being accessed, leading to uninitialized memory reads that trigger warnings under debug configurations. The fix involves early return in the checksum update function to avoid reading uninitialized transport header offsets for IPv6 fragments.

Impact

The impact is limited to triggering debug warnings due to uninitialized transport header access when processing IPv6 fragments in Open vSwitch. There is no indication of a security breach, crash, or other adverse effects beyond debug warnings. The issue is harmless in normal operation but can cause noise in debug logs.

Summary

The Linux kernel Open vSwitch module had a flaw in set_ipv6_addr() when handling IPv6 fragments. Specifically, parse_ipv6hdr() sets the protocol to NEXTHDR_FRAGMENT and returns early without setting the transport header for non-first fragments. Subsequently, update_ipv6_checksum() unconditionally accesses the transport header offset, which is uninitialized in this case, causing debug warnings. The patch adds an early return in update_ipv6_checksum() if the protocol is NEXTHDR_FRAGMENT, preventing the access of uninitialized transport header data while preserving debug warnings for other protocols. This resolves harmless but noisy warnings triggered under CONFIG_DEBUG_NET=y.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 26 Oct 2026, 15:04 UTC

Technical details

References

Community reviews

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