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NVD / CVE Program· CNA Linux

CVE-2026-23159: perf: sched: Fix perf crash with new is_user_task() helper

Noroxi assessment

Priority: Monitor (action score 22/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.13% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 5aac392fcd3d981d7997f1a0766829e1afdeac2e, 6.12.69, 6.18.

Low priority for now. Upgrade to Linux Linux 5aac392fcd3d981d7997f1a0766829e1afdeac2e, 6.12.69, 6.18 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: perf: sched: Fix perf crash with new is_user_task() helper In order to do a user space stacktrace the current task needs to be a user task that has executed in user space. It use to be possible to test if a task is a user task or not by simply checking the task_struct mm field. If it was non NULL, it was a user task and if not it was a kernel task. But things have changed over time, and some kernel tasks now have their own mm field. An idea was made to instead test PF_KTHREAD and two functions were used to wrap this check in case it became more complex to test if a task was a user task or not[1]. But this was rejected and the C code simply checked the PF_KTHREAD directly. It was later found that not all kernel threads set PF_KTHREAD. The io-uring helpers instead set PF_USER_WORKER and this needed to be added as well. But checking the flags is still not enough. There's a very small window when a task exits that it frees its mm field and it is set back to NULL. If perf were to trigger at this moment, the flags test would say its a user space task but when perf would read the mm field it would crash with at NULL pointer dereference. Now there are flags that can be used to test if a task is exiting, but they are set in areas that perf may still want to profile the user space task (to see where it exited). The only real test is to check both the flags and the mm field. Instead of making this modification in every location, create a new is_user_task() helper function that does all the tests needed to know if it is safe to read the user space memory or not. [1] https://lore.kernel.org/all/20250425204120.639530125@goodmis.org/

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Feb 14, 2026
Updated
Jun 17, 2026
EPSS
0.1% · 2th percentile

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

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  • Not in KEV: no record of exploitation in the wild
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  • A fix has been released

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel6.6.116 and later · before 6.6.123
  • linux linux kernel6.12.57 and later · before 6.12.69
  • linux linux kernel6.17.7 and later · before 6.18.9
  • linux linux kernel6.19

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 5050083e1a2f3e5e29cee0205c40e5864b52601d, 6.18affected
    • 34b5aba8511a12fb2e9bd3124835cb4087187dac and later · before d84a4836dc246b7dc244e46a08ff992956b68db0affected · git
    • 8d79f96e477c4b8e3fca2efb36b269d8960a2285 and later · before 5aac392fcd3d981d7997f1a0766829e1afdeac2eaffected · git
    • 90942f9fac05702065ff82ed0bade0d08168d4ea and later · before a28fce0365e1cb9cb8c04c893b9334e5ca9d9f1caffected · git
    • 90942f9fac05702065ff82ed0bade0d08168d4ea and later · before 76ed27608f7dd235b727ebbb12163438c2fbb617affected · git
    • 6.6.116 and later · before 6.6.123affected · semver
    • 6.12.57 and later · before 6.12.69affected · semver
    • 6.17.7 and later · before 6.18affected · semver
    • before 6.18not affected · semver
    • 6.6.123 and later · up to and including 6.6.*not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:13linuxbefore 6.12.69-16.12.69-1
Debian:14linuxbefore 6.18.9-16.18.9-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2026-23156Feb 14, 2026 · efivarfs: fix error propagation in efivar_entry_get()
    31Monitor
  • ← EarlierCVE-2026-23158Feb 14, 2026 · gpio: virtuser: fix UAF in configfs release path
    31Monitor
  • Later →CVE-2026-23161Feb 14, 2026 · mm/shmem, swap: fix race of truncate and swap entry split
    18Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux5aac392fcd3d981d7997f1a0766829e1afdeac2eVendor (CNA)
Linux Linux6.12.69Vendor (CNA)
Linux Linux6.18Vendor (CNA)
Linux Linux6.6.123Vendor (CNA)
Linux Linux76ed27608f7dd235b727ebbb12163438c2fbb617Vendor (CNA)
Linux Linuxa28fce0365e1cb9cb8c04c893b9334e5ca9d9f1cVendor (CNA)
Linux Linuxd84a4836dc246b7dc244e46a08ff992956b68db0Vendor (CNA)
debian:linux6.12.69-1 · Debian:13Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-476 · NULL Pointer Dereference

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (3 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records