VulnerabilityPublished 18 Oct 2026

CVE-2026-98541: Linux kernel · fou: reject omitted FOU_ATTR_IPPROTO on FOU_ENCAP_DIRECT

Source GCVE Database

Authoritative record:CVE-2026-98541· Medium

Not known to be exploited · fixed in fd20220f86947d66d4dba2d76f13a28dbd86ef30 : update Linux kernel when convenient.

Data as of 26 Oct 2026, 17:16 UTC

Severity

Medium

Rated by Threat Radar · CVSS not yet scored by NVD

EPSS: 0.2% chance of exploitation in 30 days – higher than 11% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in fd20220f86947d66d4dba2d76f13a28dbd86ef30, d22609f3d13fc5baacd92c222731b03c593401db, b1229b210ef5a39c58be665e6798203751411842 +5

Exploitation evidence

Disclosed: evidence found.
CVE published 18 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-rj48-hq74-h6fv

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 23461551c00628c3f3fe9cf837bf53cf8f212b63, < fd20220f86947d66d4dba2d76f13a28dbd86ef30	Fixed in fd20220f86947d66d4dba2d76f13a28dbd86ef30
LinuxLinux	Affected ≥ 23461551c00628c3f3fe9cf837bf53cf8f212b63, < d22609f3d13fc5baacd92c222731b03c593401db	Fixed in d22609f3d13fc5baacd92c222731b03c593401db
LinuxLinux	Affected ≥ 23461551c00628c3f3fe9cf837bf53cf8f212b63, < b1229b210ef5a39c58be665e6798203751411842	Fixed in b1229b210ef5a39c58be665e6798203751411842
LinuxLinux	Affected ≥ 23461551c00628c3f3fe9cf837bf53cf8f212b63, < 520cf06b8ea0ba5bcc1b8b982ef07f02b5e56221	Fixed in 520cf06b8ea0ba5bcc1b8b982ef07f02b5e56221
LinuxLinux	Affected ≥ 23461551c00628c3f3fe9cf837bf53cf8f212b63, < 46b1ffb7e169c7e401dd890b29e55dbc261f8f01	Fixed in 46b1ffb7e169c7e401dd890b29e55dbc261f8f01
LinuxLinux	Affected ≥ 23461551c00628c3f3fe9cf837bf53cf8f212b63, < 8b43f40798bb2758489fbbcae7e841ad4443c213	Fixed in 8b43f40798bb2758489fbbcae7e841ad4443c213

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A patch has been applied to the Linux kernel that rejects creation of FOU_ENCAP_DIRECT sockets without the FOU_ATTR_IPPROTO attribute, returning an error and preventing the memory leak. Users should update to a kernel version that includes this fix. No other mitigation actions are indicated or necessary.

Description

A vulnerability in the Linux kernel's fou (foo-over-UDP) module allowed creation of a FOU_ENCAP_DIRECT socket without specifying the required FOU_ATTR_IPPROTO attribute, leading to a memory leak of sk_buff structures when receiving packets. The issue was fixed by rejecting attempts to create such sockets without the protocol attribute, preventing the leak.

References

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