VulnerabilityPublished 7 Nov 2026

CVE-2026-99277: Linux kernel · ksmbd: hold a connection reference for each session channel

Source GCVE Database

Compare

Authoritative record:CVE-2026-99277· Medium

Not known to be exploited · fixed in add8d7fb04efe564193df73581889c62fc0016f1 : update Linux kernel when convenient.

Data as of 7 Nov 2026, 16:17 UTC

Severity

Medium

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

Thin evidence

One scorer or none

Patch: Available – fixed in add8d7fb04efe564193df73581889c62fc0016f1, 7.3, 4b333aed69cfc2c8687b86b6a4364a0dffc16dd8

Exploitation evidence

Disclosed: evidence found.
CVE published 7 Nov 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 7 Nov 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.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), 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-p59r-fqh3-3h8x

What to do

Upgrade Linux kernel to add8d7fb04efe564193df73581889c62fc0016f1, 7.3 or 4b333aed69cfc2c8687b86b6a4364a0dffc16dd8.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected >=7.2.8 <7.3	Fixed in add8d7fb04efe564193df73581889c62fc0016f1 7.3 4b333aed69cfc2c8687b86b6a4364a0dffc16dd8
LinuxLinux	Affected =7.3	Fixed in–

AI-suggested

A fix has been implemented in the Linux kernel to hold a connection reference for each session channel until the session is destroyed. Users should apply the official kernel updates that include this fix. No additional mitigation steps are indicated.

Description

A vulnerability in the Linux kernel's ksmbd component involves improper handling of connection references for session channels. The flaw allows a connection to be freed while still being accessed by another session reference holder, potentially leading to use-after-free conditions during SMB3.1.1 binding or procfs reads. The issue is addressed by holding a connection reference for each session channel until the session is fully destroyed.

Impact

The vulnerability can lead to use-after-free conditions where a connection object is freed while still being accessed by session channels. This may cause kernel instability or crashes during SMB3.1.1 binding or procfs reads. No known exploits in the wild have been reported.

Summary

CVE-2026-99277 describes a vulnerability in the Linux kernel's ksmbd subsystem where ksmbd_session_unregister() removes a session from global and per-connection tables before dropping the table reference. This can result in a concurrent reference holder keeping the session and its channel list alive after removal, causing connection cleanup to fail to find the unpublished session and remove its channels. Since channels only store a raw connection pointer, the connection can be freed while still accessed by another session reference holder, for example during SMB3.1.1 binding or procfs read operations. The fix involves taking a connection reference when registering a channel and releasing it on insertion failure, channel removal, or final session destruction, ensuring channels and signing keys persist until session destruction to allow response signing after session unregistration.

References

Community reviews

Loading reviews…