VulnerabilityPublished 18 Oct 2026

CVE-2026-98449: Linux kernel · smb: client: delete compound mids on send failure before unlock

Source GCVE Database

Authoritative record:CVE-2026-98449· Low

Not known to be exploited · fixed in 70783946f3b5d0c06ec7df0f5e7bec2bfad24efb : update Linux kernel when convenient.

Data as of 26 Oct 2026, 13:47 UTC

Severity

Low

Rated by Threat Radar · CVSS not yet scored by NVD

EPSS: 0.1% chance of exploitation in 30 days – higher than 5% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 70783946f3b5d0c06ec7df0f5e7bec2bfad24efb, 8f6f8a48399f82f4a83f7b9f25b9707e0062a4f9, 4.21

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-2758-q84j-4rxj

What to do

Upgrade Linux kernel to 70783946f3b5d0c06ec7df0f5e7bec2bfad24efb, 8f6f8a48399f82f4a83f7b9f25b9707e0062a4f9 or 4.21.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected >=4.20.11 <4.21	Fixed in 70783946f3b5d0c06ec7df0f5e7bec2bfad24efb 8f6f8a48399f82f4a83f7b9f25b9707e0062a4f9 4.21
LinuxLinux	Affected =5.0	Fixed in–

AI-suggested

A fix has been implemented in the Linux kernel to delete compound mids on send failure before unlocking the server and to mark them as cancelled to avoid double deletion. Users should apply the official kernel updates that include this fix. Patch status is not explicitly confirmed in the provided data; check the vendor advisory for current remediation guidance.

Description

A vulnerability in the Linux kernel's SMB client was resolved involving improper handling of compound mids during send failures. When a compound request fails to send, the system incorrectly manages mids on the pending queue, leading to double decrementing of in-flight credits and kernel warnings. This issue was identified during SMB2 negotiation when socket send failures occur.

Impact

This vulnerability causes incorrect credit accounting in the SMB client, leading to kernel warnings and potential instability during SMB2 negotiation failures. There is no indication of remote code execution or privilege escalation. The impact is primarily on kernel stability and error handling during network communication failures.

Summary

The Linux kernel SMB client had a flaw where, upon failure to send a compound request, the mids on the pending_mid_q were not deleted before unlocking the server. This caused cifs_abort_connection() to invoke callbacks that returned credits and decremented in_flight counters prematurely. Subsequently, the send-error path returned the same credits again, resulting in in_flight being decremented twice and triggering warnings in smb2_add_credits(). The fix involved deleting mids on send failure before unlocking and marking them as cancelled to prevent double deletion.

References

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