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NVD / CVE Program· CNA Linux

CVE-2026-52977: futex: Prevent lockup in requeue-PI during signal/ timeout wakeup

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: 0.12% (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 0304d60abb9dcc02bc7fe6d1850f4ca206e8f1a0, 0aacb6d18f76552e3e0ee25d9f40d21b3486f4cf, 4e0ed44e51727d56244a822ab941efe507c47966; azl3 kernel 6.6.139.1-1 on Azure Linux 3.0 6.6.143.1-1.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 0304d60abb9dcc02bc7fe6d1850f4ca206e8f1a0, 0aacb6d18f76552e3e0ee25d9f40d21b3486f4cf, 4e0ed44e51727d56244a822ab941efe507c47966; azl3 kernel 6.6.139.1-1 on Azure Linux 3.0 6.6.143.1-1 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: futex: Prevent lockup in requeue-PI during signal/ timeout wakeup During wait-requeue-pi (task A) and requeue-PI (task B) the following race can happen: Task A Task B futex_wait_requeue_pi() futex_setup_timer() futex_do_wait() futex_requeue() CLASS(hb, hb1)(&key1); CLASS(hb, hb2)(&key2); *timeout* futex_requeue_pi_wakeup_sync() requeue_state = Q_REQUEUE_PI_IGNORE *blocks on hb->lock* futex_proxy_trylock_atomic() futex_requeue_pi_prepare() Q_REQUEUE_PI_IGNORE => -EAGAIN double_unlock_hb(hb1, hb2) *retry* Task B acquires both hb locks and attempts to acquire the PI-lock of the top most waiter (task B). Task A is leaving early due to a signal/ timeout and started removing itself from the queue. It updates its requeue_state but can not remove it from the list because this requires the hb lock which is owned by task B. Usually task A is able to swoop the lock after task B unlocked it. However if task B is of higher priority then task A may not be able to wake up in time and acquire the lock before task B gets it again. Especially on a UP system where A is never scheduled. As a result task A blocks on the lock and task B busy loops, trying to make progress but live locks the system instead. Tragic. This can be fixed by removing the top most waiter from the list in this case. This allows task B to grab the next top waiter (if any) in the next iteration and make progress. Remove the top most waiter if futex_requeue_pi_prepare() fails. Let the waiter conditionally remove itself from the list in handle_early_requeue_pi_wakeup().

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Jun 24, 2026
Updated
Nov 6, 2026
EPSS
0.1% · 2th percentile
CWE
—

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%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • 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 kernel5.15 and later · before 6.1.175
  • linux linux kernel6.2 and later · before 6.6.141
  • linux linux kernel6.7 and later · before 6.12.91
  • linux linux kernel6.13 and later · before 6.18.33
  • linux linux kernel6.19 and later · before 7.0.10
  • linux linux kernel7.1

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

    • 5.15affected
    • 07d91ef510fb16a2e0ca7453222105835b7ba3b8 and later · before e5dbae3572757cecc3d3ec7cf96cbcc9cd9f016caffected · git
    • 07d91ef510fb16a2e0ca7453222105835b7ba3b8 and later · before 4e0ed44e51727d56244a822ab941efe507c47966affected · git
    • 07d91ef510fb16a2e0ca7453222105835b7ba3b8 and later · before e3f95b1ba242e37093305812df7fdbe7288a43acaffected · git
    • 07d91ef510fb16a2e0ca7453222105835b7ba3b8 and later · before 0aacb6d18f76552e3e0ee25d9f40d21b3486f4cfaffected · git
    • 07d91ef510fb16a2e0ca7453222105835b7ba3b8 and later · before 69a7cfc66405aeaa2483147653d031b3592ffc9caffected · git
    • 07d91ef510fb16a2e0ca7453222105835b7ba3b8 and later · before 0304d60abb9dcc02bc7fe6d1850f4ca206e8f1a0affected · git
    • 07d91ef510fb16a2e0ca7453222105835b7ba3b8 and later · before bc7304f3ae20972d11db6e0b1b541c63feda5f05affected · git
    • before 5.15not affected · semver
    • 5.15.216 and later · up to and including 5.15.*not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
AlmaLinux:9kernelbefore 5.14.0-687.36.1.el9_85.14.0-687.36.1.el9_8
AlmaLinux:9kernel-64kbefore 5.14.0-687.36.1.el9_85.14.0-687.36.1.el9_8
AlmaLinux:9kernel-64k-corebefore 5.14.0-687.36.1.el9_85.14.0-687.36.1.el9_8
AlmaLinux:9kernel-64k-debugbefore 5.14.0-687.36.1.el9_85.14.0-687.36.1.el9_8
AlmaLinux:9kernel-64k-debug-corebefore 5.14.0-687.36.1.el9_85.14.0-687.36.1.el9_8
AlmaLinux:9kernel-64k-debug-develbefore 5.14.0-687.36.1.el9_85.14.0-687.36.1.el9_8
AlmaLinux:9kernel-64k-debug-devel-matchedbefore 5.14.0-687.36.1.el9_85.14.0-687.36.1.el9_8
AlmaLinux:9kernel-64k-debug-modulesbefore 5.14.0-687.36.1.el9_85.14.0-687.36.1.el9_8
AlmaLinux:9kernel-64k-debug-modules-corebefore 5.14.0-687.36.1.el9_85.14.0-687.36.1.el9_8
AlmaLinux:9kernel-64k-debug-modules-extrabefore 5.14.0-687.36.1.el9_85.14.0-687.36.1.el9_8
AlmaLinux:9kernel-64k-develbefore 5.14.0-687.36.1.el9_85.14.0-687.36.1.el9_8
AlmaLinux:9kernel-64k-devel-matchedbefore 5.14.0-687.36.1.el9_85.14.0-687.36.1.el9_8
AlmaLinux:9kernel-64k-modulesbefore 5.14.0-687.36.1.el9_85.14.0-687.36.1.el9_8
AlmaLinux:9kernel-64k-modules-corebefore 5.14.0-687.36.1.el9_85.14.0-687.36.1.el9_8
AlmaLinux:9kernel-64k-modules-extrabefore 5.14.0-687.36.1.el9_85.14.0-687.36.1.el9_8
AlmaLinux:9kernel-abi-stablelistsbefore 5.14.0-687.36.1.el9_85.14.0-687.36.1.el9_8
AlmaLinux:9kernel-corebefore 5.14.0-687.36.1.el9_85.14.0-687.36.1.el9_8
AlmaLinux:9kernel-cross-headersbefore 5.14.0-687.36.1.el9_85.14.0-687.36.1.el9_8
AlmaLinux:9kernel-debugbefore 5.14.0-687.36.1.el9_85.14.0-687.36.1.el9_8
AlmaLinux:9kernel-debug-corebefore 5.14.0-687.36.1.el9_85.14.0-687.36.1.el9_8
AlmaLinux:9kernel-debug-develbefore 5.14.0-687.36.1.el9_85.14.0-687.36.1.el9_8
AlmaLinux:9kernel-debug-devel-matchedbefore 5.14.0-687.36.1.el9_85.14.0-687.36.1.el9_8
AlmaLinux:9kernel-debug-modulesbefore 5.14.0-687.36.1.el9_85.14.0-687.36.1.el9_8
AlmaLinux:9kernel-debug-modules-corebefore 5.14.0-687.36.1.el9_85.14.0-687.36.1.el9_8

+96

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-2026-52975Jun 24, 2026 · bonding: 3ad: implement proper RCU rules for port->aggregator
    31Monitor
  • ← EarlierCVE-2026-52976Jun 24, 2026 · drm/xe: Fix error cleanup in xe_exec_queue_create_ioctl()
    31Monitor
  • Later →CVE-2026-52981Jun 24, 2026 · neigh: let neigh_xmit take skb ownership
    30Monitor

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 Linux0304d60abb9dcc02bc7fe6d1850f4ca206e8f1a0Vendor (CNA)
Linux Linux0aacb6d18f76552e3e0ee25d9f40d21b3486f4cfVendor (CNA)
Linux Linux4e0ed44e51727d56244a822ab941efe507c47966Vendor (CNA)
Linux Linux69a7cfc66405aeaa2483147653d031b3592ffc9cVendor (CNA)
Linux Linuxbc7304f3ae20972d11db6e0b1b541c63feda5f05Vendor (CNA)
Linux Linuxe3f95b1ba242e37093305812df7fdbe7288a43acVendor (CNA)
Linux Linuxe5dbae3572757cecc3d3ec7cf96cbcc9cd9f016cVendor (CNA)
azl3 kernel 6.6.139.1-1 on Azure Linux 3.06.6.143.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
almalinux:kernel5.14.0-687.36.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k5.14.0-687.36.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-core5.14.0-687.36.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug5.14.0-687.36.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-core5.14.0-687.36.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-devel5.14.0-687.36.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-devel-matched5.14.0-687.36.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-modules5.14.0-687.36.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-modules-core5.14.0-687.36.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-modules-extra5.14.0-687.36.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-devel5.14.0-687.36.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-devel-matched5.14.0-687.36.1.el9_8 · AlmaLinux:9Package registry (OSV)
debian:linux6.1.176-1 · Debian:12Package registry (OSV)
red hat:kernel-64k-debug-debuginfo0:5.14.0-687.36.1.el9_8 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:kernel-64k-debug-devel0:5.14.0-687.36.1.el9_8 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:kernel-64k-debug-devel-matched0:5.14.0-687.36.1.el9_8 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:kernel-64k-debuginfo0:5.14.0-687.36.1.el9_8 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:kernel-64k-devel0:5.14.0-687.36.1.el9_8 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:kernel-64k-devel-matched0:5.14.0-687.36.1.el9_8 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:kernel-debug-debuginfo0:5.14.0-687.36.1.el9_8 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:kernel-debug-devel0:5.14.0-687.36.1.el9_8 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:kernel-debug-devel-matched0:5.14.0-687.36.1.el9_8 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)

+15

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).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

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)

—

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. SSVC exploitation— → none
  2. Fix✗ → ✓

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

References

Show all references (6 more)

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

All records