CVE-2025-38723

CPU soft lockup via negative tail-call offset

Published Sep 4, 2025 · Updated May 12, 2026

Improper input validation in the LoongArch BPF JIT in Linux allows local users to trigger a CPU soft lockup through BPF tail calls. An extra bpf_int_jit_compile pass skips JIT-context initialization, leaves out_offset at -1, and makes emit_bpf_tail_call generate a negative jump offset. Successful triggering requires a LoongArch system and the ability to load the affected BPF tail-call workload; the documented consequence is a watchdog-reported CPU stall.

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

What happened

Improper input validation in the LoongArch BPF JIT in Linux allows local users to trigger a CPU soft lockup through BPF tail calls. An extra bpf_int_jit_compile pass skips JIT-context initialization, leaves out_offset at -1, and makes emit_bpf_tail_call generate a negative jump offset. Successful triggering requires a LoongArch system and the ability to load the affected BPF tail-call workload; the documented consequence is a watchdog-reported CPU stall.

The record

CVE
CVE-2025-38723
Published
Sep 4, 2025
Updated
May 12, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-20, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 4, 2025CVE publishedPublication date reported by the CVE source.
  2. May 12, 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=5dc615520c4dfb358245680f1904bad61116648e <17c010fe45def335fe03a0718935416b04c7f349
  2. Affected versionversion=5dc615520c4dfb358245680f1904bad61116648e <1a782fa32e644aa9fbae6c8488f3e61221ac96e1
  3. Affected versionversion=5dc615520c4dfb358245680f1904bad61116648e <9262e3e04621558e875eb5afb5e726b648cd5949
  4. Affected versionversion=5dc615520c4dfb358245680f1904bad61116648e <cd39d9e6b7e4c58fa77783e7aedf7ada51d02ea3
  5. Affected versionversion=5dc615520c4dfb358245680f1904bad61116648e <f2b5e50cc04d7a049b385bc1c93b9cbf5f10c94f
  6. Affected versionversion=5dc615520c4dfb358245680f1904bad61116648e <f83d469e16bb1f75991ca67c56786fb2aaa42bea
  7. Affected versionversion=6.1

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5dc615520c4dfb358245680f1904bad61116648e <17c010fe45def335fe03a0718935416b04c7f349; version=5dc615520c4dfb358245680f1904bad61116648e <1a782fa32e644aa9fbae6c8488f3e61221ac96e1; version=5dc615520c4dfb358245680f1904bad61116648e <9262e3e04621558e875eb5afb5e726b648cd5949; version=5dc615520c4dfb358245680f1904bad61116648e <cd39d9e6b7e4c58fa77783e7aedf7ada51d02ea3; version=5dc615520c4dfb358245680f1904bad61116648e <f2b5e50cc04d7a049b385bc1c93b9cbf5f10c94f; version=5dc615520c4dfb358245680f1904bad61116648e <f83d469e16bb1f75991ca67c56786fb2aaa42bea; version=6.1
Siemens · SIMATIC CN 4100version=0 <V5.0

Published CVSS scores

5.5Siemens ProductCERTCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
T1499Endpoint Denial of Service

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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