CVE-2025-37963

Performance degradation via overbroad cBPF mitigation

Published May 20, 2025 · Updated May 11, 2026

Excessive BHB mitigation in the arm64 BPF JIT in Linux 3.7 and later allows local users to degrade cBPF execution performance. The build_bhb_mitigation function emits branch-history-clearing instructions for every cBPF program without skipping programs loaded with CAP_SYS_ADMIN. Reaching the unnecessary path requires local CAP_SYS_ADMIN access on an arm64 system that uses the BHB mitigation, and the documented consequence is a slight performance penalty rather than a crash or data loss.

CVSS severity5.5
Medium
EPSS probability0.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Excessive BHB mitigation in the arm64 BPF JIT in Linux 3.7 and later allows local users to degrade cBPF execution performance. The build_bhb_mitigation function emits branch-history-clearing instructions for every cBPF program without skipping programs loaded with CAP_SYS_ADMIN. Reaching the unnecessary path requires local CAP_SYS_ADMIN access on an arm64 system that uses the BHB mitigation, and the documented consequence is a slight performance penalty rather than a crash or data loss.

The record

CVE
CVE-2025-37963
Published
May 20, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. May 20, 2025CVE publishedPublication date reported by the CVE source.
  2. May 11, 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=0be7320a635c2e434e8b67e0e9474a85ceb421c4 <038866e01ea5e5a3d948898ac216e531e7848669
  2. Affected versionversion=0be7320a635c2e434e8b67e0e9474a85ceb421c4 <477481c4348268136227348984b6699d6370b685
  3. Affected versionversion=0be7320a635c2e434e8b67e0e9474a85ceb421c4 <6e52d043f7dbf1839a24a3fab2b12b0d3839de7a
  4. Affected versionversion=0be7320a635c2e434e8b67e0e9474a85ceb421c4 <80251f62028f1ab2e09be5ca3123f84e8b00389a
  5. Affected versionversion=0be7320a635c2e434e8b67e0e9474a85ceb421c4 <df53d418709205450a02bb4d71cbfb4ff86f2c1e
  6. Affected versionversion=0be7320a635c2e434e8b67e0e9474a85ceb421c4 <e5f5100f1c64ac6c72671b2cf6b46542fce93706
  7. Affected versionversion=0be7320a635c2e434e8b67e0e9474a85ceb421c4 <f300769ead032513a68e4a02e806393402e626f8
  8. Affected versionversion=3.7

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linuxversion=0be7320a635c2e434e8b67e0e9474a85ceb421c4 <038866e01ea5e5a3d948898ac216e531e7848669; version=0be7320a635c2e434e8b67e0e9474a85ceb421c4 <477481c4348268136227348984b6699d6370b685; version=0be7320a635c2e434e8b67e0e9474a85ceb421c4 <6e52d043f7dbf1839a24a3fab2b12b0d3839de7a; version=0be7320a635c2e434e8b67e0e9474a85ceb421c4 <80251f62028f1ab2e09be5ca3123f84e8b00389a; version=0be7320a635c2e434e8b67e0e9474a85ceb421c4 <df53d418709205450a02bb4d71cbfb4ff86f2c1e; version=0be7320a635c2e434e8b67e0e9474a85ceb421c4 <e5f5100f1c64ac6c72671b2cf6b46542fce93706; version=0be7320a635c2e434e8b67e0e9474a85ceb421c4 <f300769ead032513a68e4a02e806393402e626f8; version=3.7

Published CVSS scores

5.5NIST National Vulnerability DatabaseCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
6.4OracleCVSS:3.1/AV:L/AC:H/PR:H/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.

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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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499Endpoint Denial of Service

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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