CVE-2026-52977

System livelock via futex requeue-PI race

Published Jun 24, 2026 · Updated Jun 24, 2026

Denial of service in the Linux kernel allows local users to livelock the system through a futex requeue-PI race during wakeup. A signal or timeout makes the top waiter mark its requeue state as ignored while it remains queued behind a hash-bucket lock; the requeue task then retries without removing that waiter. A higher-priority requeue task can repeatedly reacquire both locks before the waiter runs, causing a busy loop that can stall the entire system, especially on a uniprocessor host.

CVSS severity5.5
Medium
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in the Linux kernel allows local users to livelock the system through a futex requeue-PI race during wakeup. A signal or timeout makes the top waiter mark its requeue state as ignored while it remains queued behind a hash-bucket lock; the requeue task then retries without removing that waiter. A higher-priority requeue task can repeatedly reacquire both locks before the waiter runs, causing a busy loop that can stall the entire system, especially on a uniprocessor host.

The record

CVE
CVE-2026-52977
Published
Jun 24, 2026
Updated
Jun 24, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 24, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=07d91ef510fb16a2e0ca7453222105835b7ba3b8 <0304d60abb9dcc02bc7fe6d1850f4ca206e8f1a0
  2. Affected versionversion=07d91ef510fb16a2e0ca7453222105835b7ba3b8 <0aacb6d18f76552e3e0ee25d9f40d21b3486f4cf
  3. Affected versionversion=07d91ef510fb16a2e0ca7453222105835b7ba3b8 <4e0ed44e51727d56244a822ab941efe507c47966
  4. Affected versionversion=07d91ef510fb16a2e0ca7453222105835b7ba3b8 <69a7cfc66405aeaa2483147653d031b3592ffc9c
  5. Affected versionversion=07d91ef510fb16a2e0ca7453222105835b7ba3b8 <bc7304f3ae20972d11db6e0b1b541c63feda5f05
  6. Affected versionversion=07d91ef510fb16a2e0ca7453222105835b7ba3b8 <e3f95b1ba242e37093305812df7fdbe7288a43ac
  7. Affected versionversion=5.15

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=07d91ef510fb16a2e0ca7453222105835b7ba3b8 <0304d60abb9dcc02bc7fe6d1850f4ca206e8f1a0; version=07d91ef510fb16a2e0ca7453222105835b7ba3b8 <0aacb6d18f76552e3e0ee25d9f40d21b3486f4cf; version=07d91ef510fb16a2e0ca7453222105835b7ba3b8 <4e0ed44e51727d56244a822ab941efe507c47966; version=07d91ef510fb16a2e0ca7453222105835b7ba3b8 <69a7cfc66405aeaa2483147653d031b3592ffc9c; version=07d91ef510fb16a2e0ca7453222105835b7ba3b8 <bc7304f3ae20972d11db6e0b1b541c63feda5f05; version=07d91ef510fb16a2e0ca7453222105835b7ba3b8 <e3f95b1ba242e37093305812df7fdbe7288a43ac; version=5.15

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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