CVE-2026-53260Network attack vector

System interruption via TCP request-socket refcount race

Published Jun 25, 2026 · Updated Jun 25, 2026

Use-after-free in affected Linux Kernel releases allows remote attackers to interrupt systems through TCP SYN traffic. In reqsk_queue_hash_req(), PREEMPT_RT can schedule the request timer after mod_timer() but before refcount_set(), leaving the ehash and timer references uncounted. The race requires PREEMPT_RT, an exposed TCP listener, listener closure, and timer expiry; duplicate reqsk_put() calls then underflow the reference count.

CVSS severity9.8
Critical
EPSS probability0.37%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in affected Linux Kernel releases allows remote attackers to interrupt systems through TCP SYN traffic. In reqsk_queue_hash_req(), PREEMPT_RT can schedule the request timer after mod_timer() but before refcount_set(), leaving the ehash and timer references uncounted. The race requires PREEMPT_RT, an exposed TCP listener, listener closure, and timer expiry; duplicate reqsk_put() calls then underflow the reference count.

The record

CVE
CVE-2026-53260
Published
Jun 25, 2026
Updated
Jun 25, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-416, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 25, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 25, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=6.12
  2. Affected versionversion=d2d6422f8bd17c6bb205133e290625a564194496 <b183215ff714efb747d9d5a429322ba6404b5401
  3. Affected versionversion=d2d6422f8bd17c6bb205133e290625a564194496 <e10902df24488ca722303133acfc82490f7d59ad

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=6.12; version=d2d6422f8bd17c6bb205133e290625a564194496 <b183215ff714efb747d9d5a429322ba6404b5401; version=d2d6422f8bd17c6bb205133e290625a564194496 <e10902df24488ca722303133acfc82490f7d59ad

Published CVSS scores

9.8kernel.orgCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

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

Weakness, pattern, technique

CWE-416Use After Free
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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