VulnerabilityPublished 18 Oct 2026

CVE-2026-98858: Linux kernel · io_uring: fix task_work add use-after-free with SQPOLL

Source GCVE Database

Authoritative record:CVE-2026-98858· High

Not known to be exploited · fixed in a92193c91e8839fe5fc209616ea95465ae4b919d : patch Linux kernel soon.

Data as of 26 Oct 2026, 12:55 UTC

Severity

High

Rated by Threat Radar · CVSS not yet scored by NVD

EPSS: 0.1% chance of exploitation in 30 days – higher than 4% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in a92193c91e8839fe5fc209616ea95465ae4b919d, 891bd8335a0de3bb15c3b797ce3026bbb0dbef6c, 395b25968fe854d4efaa19a8e9b7a5b6d1b3eea3 +1

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-v42g-qm29-227m

What to do

Upgrade Linux kernel to a92193c91e8839fe5fc209616ea95465ae4b919d, 891bd8335a0de3bb15c3b797ce3026bbb0dbef6c, 395b25968fe854d4efaa19a8e9b7a5b6d1b3eea3 or 42b3332efacfd2140be4cd0dedad4fb96b8ae90e.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ af5d68f8892f8ee8f137648b79ceb2abc153a19b, < a92193c91e8839fe5fc209616ea95465ae4b919d	Fixed in a92193c91e8839fe5fc209616ea95465ae4b919d
LinuxLinux	Affected ≥ af5d68f8892f8ee8f137648b79ceb2abc153a19b, < 891bd8335a0de3bb15c3b797ce3026bbb0dbef6c	Fixed in 891bd8335a0de3bb15c3b797ce3026bbb0dbef6c
LinuxLinux	Affected ≥ af5d68f8892f8ee8f137648b79ceb2abc153a19b, < 395b25968fe854d4efaa19a8e9b7a5b6d1b3eea3	Fixed in 395b25968fe854d4efaa19a8e9b7a5b6d1b3eea3
LinuxLinux	Affected ≥ af5d68f8892f8ee8f137648b79ceb2abc153a19b, < 42b3332efacfd2140be4cd0dedad4fb96b8ae90e	Fixed in 42b3332efacfd2140be4cd0dedad4fb96b8ae90e
LinuxLinux	Affected =6.9	Fixed in–
Linuxlinux/kernel`pkg:deb/linux/kernel`Other threats	Affected =6.9	Fixed in–

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

AI-suggested

A fix has been implemented in the Linux kernel to address this use-after-free vulnerability by adding proper synchronization with RCU locks and grace periods. Users should update to the patched kernel version once available. No additional mitigation steps are indicated.

Description

A use-after-free vulnerability in the Linux kernel's io_uring implementation with SQPOLL mode has been resolved. The issue occurs because the sqpoll thread processes task_work independently, potentially freeing resources while another function still accesses them. This leads to a use-after-free condition detected by KASAN. The fix involves holding an RCU read lock during task_work addition and waiting for a grace period before freeing resources.

References

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