CVE-2026-89902

Local socket cgroup policy bypass via breakpoint

Published Sep 16, 2026 · Updated Sep 16, 2026

Improper preemption handling in the Linux kernel on LoongArch allows local users to bypass BPF socket-creation policy. A user-issued break 11 reaches kprobe_singlestep_handler() without an active probe, which calls preempt_enable_no_resched() without the paired disable and underflows the task's preempt count. The LoongArch architecture and a BPF_CGROUP_INET_SOCK_CREATE policy are required; a socket opened in the SIGTRAP handler is attributed to the root cgroup and escapes the task's policy.

CVSS severityUnavailable
Unscored
EPSS probabilityUnavailable
No score available in this record
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper preemption handling in the Linux kernel on LoongArch allows local users to bypass BPF socket-creation policy. A user-issued break 11 reaches kprobe_singlestep_handler() without an active probe, which calls preempt_enable_no_resched() without the paired disable and underflows the task's preempt count. The LoongArch architecture and a BPF_CGROUP_INET_SOCK_CREATE policy are required; a socket opened in the SIGTRAP handler is attributed to the root cgroup and escapes the task's policy.

The record

CVE
CVE-2026-89902
Published
Sep 16, 2026
Updated
Sep 16, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1562.001
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 16, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 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=6.3
  2. Affected versionversion=6d4cc40fb5f58147defc6c0e9d86e6232fe31616 <72ce4b24676e8b3b75376c4c559dd81c1ac52d5a
  3. Affected versionversion=6d4cc40fb5f58147defc6c0e9d86e6232fe31616 <76395109a051b53860faaec96522ef08ae9e8e27
  4. Affected versionversion=6d4cc40fb5f58147defc6c0e9d86e6232fe31616 <a1cb727fa27c2d9c7859729cd90db7bc0f46957f
  5. Affected versionversion=6d4cc40fb5f58147defc6c0e9d86e6232fe31616 <c4357ebeee63cb8da1446fc936573a34e68b0f71
  6. Affected versionversion=6d4cc40fb5f58147defc6c0e9d86e6232fe31616 <ff40e597d5d98c0c45a4d09df8177202fac9520e

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=6.3; version=6d4cc40fb5f58147defc6c0e9d86e6232fe31616 <72ce4b24676e8b3b75376c4c559dd81c1ac52d5a; version=6d4cc40fb5f58147defc6c0e9d86e6232fe31616 <76395109a051b53860faaec96522ef08ae9e8e27; version=6d4cc40fb5f58147defc6c0e9d86e6232fe31616 <a1cb727fa27c2d9c7859729cd90db7bc0f46957f; version=6d4cc40fb5f58147defc6c0e9d86e6232fe31616 <c4357ebeee63cb8da1446fc936573a34e68b0f71; version=6d4cc40fb5f58147defc6c0e9d86e6232fe31616 <ff40e597d5d98c0c45a4d09df8177202fac9520e

Published CVSS scores

No CVSS assessment is available in this record.

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

T1562.001Impair Defenses: Disable or Modify Tools

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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