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Linux EUVDEUVD-2026-115765

| CVE-2026-99254
2026-11-03 Linux GHSA-g7fp-pvxq-ggj5
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Awaiting Data No severity or threat signals available yet. Label will update when CVSS score is published or threat intelligence arrives.
Patch available

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AnalysisCVE.org

In the Linux kernel, the following vulnerability has been resolved:

io_uring: don't flood a cancelling task with task_work

io_ring_exit_work() asks each task which has used the ring to remove its tctx node, by task_work, and repeats that until the list is empty. io_tctx_exit_cb() doesn't touch the node while the task is in io_uring_cancel_generic(), which removes all the nodes at its end. So the work item queues the callback again as soon as it has completed, for nothing.

That is more than a waste of time. task_work_run() only returns when it finds the list empty. If the rings are released from inside the cancellation, because requests of other rings held the last references to their files, up to 64 work items keep sending callbacks to the one task which is running them. It never finds the list empty, never gets back to the cancellation, the nodes stay, and so it goes on: a task with 60 pairs of rings which poll each other ran 280000 callbacks in 5 seconds, 20 seconds after exit_group(). It ends when all the senders happen to be late at the same time. Until then the task keeps a CPU and the work items busy.

An exiting task can't be killed meanwhile. execve() cancels the requests in the same way, so a live task can get stuck there as well, for minutes. If it takes more than five, the work items run into the WARN_ON_ONCE(time_after(jiffies, timeout)) of io_ring_exit_work(). No privilege is needed for any of this.

If the callback has met a task in cancellation, wait a little before it is sent again. Nobody has to wake the work item up for that: either the node is gone by then, or it is the turn of the next round.

Affected VersionsENISA

Linux patch: 6.1.191
Linux 5.12
Linux d56d938b4bef3e1421a42023cdcd6e13c1f50831 <14f56e9c0b8fdc2e178acdbec9781e90ef46f7e9
Linux d56d938b4bef3e1421a42023cdcd6e13c1f50831 <61c761fc21e00e45c33c2bb596be442d92fb8792
Linux patch: 6.12.115
Linux patch: 7.2.14
Linux patch: 0
Linux d56d938b4bef3e1421a42023cdcd6e13c1f50831 <a22fb44e988b01b82235ea07f0bf0fc73e256596
Linux d56d938b4bef3e1421a42023cdcd6e13c1f50831 <2c75ebae8a7f09c99e31c7042b7d4d595f03b2b1
Linux patch: 6.6.161
Linux d56d938b4bef3e1421a42023cdcd6e13c1f50831 <abdc57c7ebabaaf0b622178a6a85834e1e54ff80
Linux patch: 6.18.60

Affected Packages

euvd linux no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

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Lifecycle Timeline

2
Patch available
Nov 03, 2026 - 12:16 EUVD
CVE Published
Nov 03, 2026 - 11:20 cve.org
UNKNOWN (no severity yet)

Threat Intelligence Overview

Data Quality
1 sources
Confidence: Low

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity Not scored yet
CISA KEV No
Public POC No
EPSS N/A
Patch available Yes
Active threat No
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.
Awaiting Data No severity or threat signals available yet. Label will update when CVSS score is published or threat intelligence arrives.

Attack Technique

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.

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