CVE-2025-38120Network attack vector

Network filter bypass via stale PIPAPO map bits

Published Jul 3, 2025 · Updated Aug 5, 2026

Improper initialization in Linux kernel netfilter allows remote attackers to bypass nftables filtering through crafted packet sequences. nft_pipapo_avx2_lookup leaves result-map words beyond the first field uncleared, so bits from one lookup become false candidates in the next lookup. Exposure requires the AVX2 PIPAPO backend and a concatenated range set whose first field is smaller than its widest field; false matches can apply unintended verdicts, NAT targets, or map values.

CVSS severity9.4
Critical
EPSS probability0.45%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper initialization in Linux kernel netfilter allows remote attackers to bypass nftables filtering through crafted packet sequences. nft_pipapo_avx2_lookup leaves result-map words beyond the first field uncleared, so bits from one lookup become false candidates in the next lookup. Exposure requires the AVX2 PIPAPO backend and a concatenated range set whose first field is smaller than its widest field; false matches can apply unintended verdicts, NAT targets, or map values.

The record

CVE
CVE-2025-38120
Published
Jul 3, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 3, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 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=5.15.165 <5.15.186
  2. Affected versionversion=6.10.3 <6.11
  3. Affected versionversion=6.11
  4. Affected versionversion=6.1.103 <6.1.142
  5. Affected versionversion=6.6.44 <6.6.94
  6. Affected versionversion=69b6a67f7052905e928d75a0c5871de50e686986 <39bab2d3517b5b50c609b4f8c66129bf619fffa0
  7. Affected versionversion=77bf0c4ab928ca4c9a99311f4f70ba0c17fecba9 <8164d0efaf370c425dc69a1e8216940d09e7de0c
  8. Affected versionversion=791a615b7ad2258c560f91852be54b0480837c93 <251496ce1728c9fd47bd2b20a7b21b20b9a020ca
  9. Affected versionversion=791a615b7ad2258c560f91852be54b0480837c93 <8068e1e42b46518ce680dc6470bcd710efc3fa0a
  10. Affected versionversion=791a615b7ad2258c560f91852be54b0480837c93 <ea77c397bff8b6d59f6d83dae1425b08f465e8b5
  11. Affected versionversion=8058c88ac0df21239daee54b5934d5c80ca9685f
  12. Affected versionversion=957a4d1c4c5849e4515c9fb4db21bf85318103dc <b5ad58285f9217d68cd5ea2ad86ce254a3fe7c4d
  13. Affected versionversion=9625c46ce6fd4f922595a4b32b1de5066d70464f <90bc7f5a244aadee4292b28098b7c98aadd4b3aa

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.15.165 <5.15.186; version=6.10.3 <6.11; version=6.11; version=6.1.103 <6.1.142; version=6.6.44 <6.6.94; version=69b6a67f7052905e928d75a0c5871de50e686986 <39bab2d3517b5b50c609b4f8c66129bf619fffa0; version=77bf0c4ab928ca4c9a99311f4f70ba0c17fecba9 <8164d0efaf370c425dc69a1e8216940d09e7de0c; version=791a615b7ad2258c560f91852be54b0480837c93 <251496ce1728c9fd47bd2b20a7b21b20b9a020ca; version=791a615b7ad2258c560f91852be54b0480837c93 <8068e1e42b46518ce680dc6470bcd710efc3fa0a; version=791a615b7ad2258c560f91852be54b0480837c93 <ea77c397bff8b6d59f6d83dae1425b08f465e8b5; version=8058c88ac0df21239daee54b5934d5c80ca9685f; version=957a4d1c4c5849e4515c9fb4db21bf85318103dc <b5ad58285f9217d68cd5ea2ad86ce254a3fe7c4d; version=9625c46ce6fd4f922595a4b32b1de5066d70464f <90bc7f5a244aadee4292b28098b7c98aadd4b3aa

Published CVSS scores

5.5Amazon LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
9.4Linux CNACVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L

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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1190Exploit Public-Facing Application

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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