VulnerabilityPublished 23 Oct 2026

CVE-2026-98986: Linux kernel · namespace: remove the fsnotify marks of a mount namespace in process context

Source GCVE Database

Authoritative record:CVE-2026-98986· Medium

Not known to be exploited · fixed in 888363d74c3b5d32e2accf217add70f8b38e0e2b : 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: 0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 888363d74c3b5d32e2accf217add70f8b38e0e2b, 9e820a6becdd955a04adbedfd767253a47eedd9e, 1a116222acdcc1bc1a8350727ae6f28907d44594

Exploitation evidence

Disclosed: evidence found.
CVE published 23 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-6338-gv67-39m8

What to do

Upgrade Linux kernel to 888363d74c3b5d32e2accf217add70f8b38e0e2b, 9e820a6becdd955a04adbedfd767253a47eedd9e or 1a116222acdcc1bc1a8350727ae6f28907d44594.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ bf630c40164162ba1d3933c2f5e3397d083e0948, < 888363d74c3b5d32e2accf217add70f8b38e0e2b	Fixed in 888363d74c3b5d32e2accf217add70f8b38e0e2b
LinuxLinux	Affected ≥ bf630c40164162ba1d3933c2f5e3397d083e0948, < 9e820a6becdd955a04adbedfd767253a47eedd9e	Fixed in 9e820a6becdd955a04adbedfd767253a47eedd9e
LinuxLinux	Affected ≥ bf630c40164162ba1d3933c2f5e3397d083e0948, < 1a116222acdcc1bc1a8350727ae6f28907d44594	Fixed in 1a116222acdcc1bc1a8350727ae6f28907d44594
LinuxLinux	Affected =6.15	Fixed in–

AI-suggested

A fix has been implemented that removes the fsnotify marks in free_mnt_ns() before the namespace is handed to RCU, ensuring the removal occurs in process context and preventing the invalid context bug. Users should update to the fixed Linux kernel version once available. Patch status is not explicitly stated in the input; therefore, check the vendor advisory for current remediation guidance.

Description

A vulnerability in the Linux kernel related to the removal of fsnotify marks from a mount namespace in process context has been resolved. The issue involved improper removal of fanotify marks in an invalid context, causing kernel locking bugs and potential system instability. The flaw allowed a root user in a user namespace to leave marks on a mount namespace that could trigger a BUG due to sleeping functions called from invalid contexts during namespace release. The fix ensures marks are removed in process context before the namespace is handed to RCU, preventing the invalid context issue.

Impact

The vulnerability causes kernel BUGs due to improper locking and context usage during mount namespace release, potentially leading to system instability or crashes. It requires root privileges in a user namespace to exploit and involves manipulation of fanotify marks on mount namespaces. There is no indication of remote exploitation or privilege escalation beyond the root user in a user namespace context.

References

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