sched_ext: Wait for SCX_OPSS_DISPATCHING before moving tasks off DSQs
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
- Exploited
- No known exploitation
- Fix
- No fix listed
- Who is exposed
- Specific setups only
Do first: Check whether your setup matches what the bug needs. A task is on a non-local DSQ while the CPU that dispatched it is still running ops.dequeue() and has not cleared SCX_OPSS_DISPATCHING.
- Exploitation?/40Exploitation: unknown (data gap). No CISA SSVC exploitation rating yet
- Exposure5/25Specific setups only
- Reach20/20Affects Linux kernel (software on nearly every server, desktop or phone)
- Severity7.8/10CVSS 7.8
- No patch5/5No patch listed yet
What would change the score
- Would score about 88 if added to CISA KEV
- Would score about 83 if CISA's SSVC rates exploitation active
- Would score about 48 if CISA's SSVC rates it automatable
CVE-2026-99269 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 7.8 (high) and affects Linux; no fixed version is listed yet.
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- Published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 38/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Specific setups only
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
The Linux kernel's sched_ext scheduler subsystem is affected, where tasks can be moved between dispatch queues while the dispatching CPU is still processing them. This race condition could lead to inconsistent task state and potentially cause scheduling errors or kernel instability.
Read the original description
In the Linux kernel, the following vulnerability has been resolved: sched_ext: Wait for SCX_OPSS_DISPATCHING before moving tasks off DSQs A task can be found on a non-local DSQ while the CPU which dispatched it is still running ops.dequeue() and hasn't cleared SCX_OPSS_DISPATCHING. The DSQ consume and move paths don't wait for the dispatch to finish and can operate on the task concurrently with the dispatcher. Call scx_wait_dispatching() in scx_move_local_task_to_local_dsq(), unlink_dsq_and_switch_rq_lock() and move_task_between_dsqs() before they operate on the task. In scx_move_local_task_to_local_dsq(), wait before scx_resolve_local_dsq() as it may update p->scx.flags.
What to do
Check whether your setup matches what the bug needs.
A task is on a non-local DSQ while the CPU that dispatched it is still running ops.dequeue() and has not cleared SCX_OPSS_DISPATCHING.Workaround: The checked facts describe no workaround. The only documented detail is the timing window between dispatch and SCX_OPSS_DISPATCHING being cleared, and no mitigation is recorded for it. Check the advisory for any guidance on limiting the affected sched_ext scheduler until a fix is installed.
Timeline
- CVE published
- First seen by cve.now
- Record last updated
- Posted on X by cve.now
Affected versions
- Linux Linux
Version range not reported
- Linux Linux
7.1
Evidence 2
- Link
- Link
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-99269
Is CVE-2026-99269 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
What does this mean?
A task can sit on a non-local sched_ext dispatch queue (DSQ) while the CPU that dispatched it is still running ops.dequeue() and has not yet cleared SCX_OPSS_DISPATCHING. The kernel can move the task off that queue during this window, which the fix addresses by waiting for SCX_OPSS_DISPATCHING to clear first.Source: git.kernel.org
Which versions are affected by CVE-2026-99269?
Linux: version 7.1.Source: cve.now feed data
Am I affected, and how do I check?
The checked facts list Linux kernel as the product but give no affected version ranges. The affected setup is a sched_ext scheduler that dispatches tasks to non-local DSQs. Compare your kernel version with the version ranges in the advisory for this CVE, and check your kernel version with uname -r.Source: git.kernel.org
How do I fix CVE-2026-99269?
The checked facts name no fixed version or upgrade target. Check the kernel advisory for this CVE for the fixed version and update to a release that includes the fix.Source: git.kernel.org
What if there's no patch?
The checked facts describe no workaround. The only documented detail is the timing window between dispatch and SCX_OPSS_DISPATCHING being cleared, and no mitigation is recorded for it. Check the advisory for any guidance on limiting the affected sched_ext scheduler until a fix is installed.Source: git.kernel.org