Critical 9.4Published May 6, 2026

CVE-2026-43114netfilter: nft_set_pipapo_avx2: don't return non-matching entry on expiry

Updated under an hour ago (Oct 28, 2026, 12:50 AM ET)

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Exploited in the last 30 days

In the Linux kernel, the following vulnerability has been resolved: netfilter: nft_set_pipapo_avx2: don't return non-matching entry on expiry New test case fails unexpectedly when avx2 matching functions are used. The test first loads a ranomly generated pipapo set with 'ipv4 . port' key, i.e. nft -f foo. This works. Then, it reloads the set after a flush: (echo flush set t s; cat foo) | nft -f - This is expected to work, because its the same set after all and it was already loaded once. But with avx2, this fails: nft reports a clashing element. The reported clash is of following form: We successfully re-inserted a . b c . d Then we try to insert a . d avx2 finds the already existing a . d, which (due to 'flush set') is marked as invalid in the new generation. It skips the element and moves to next. Due to incorrect masking, the skip-step finds the next matching element *only considering the first field*, i.e. we return the already reinserted "a . b", even though the last field is different and the entry should not have been matched. No such error is reported for the generic c implementation (no avx2) or when the last field has to use the 'nft_pipapo_avx2_lookup_slow' fallback. Bisection points to 7711f4bb4b36 ("netfilter: nft_set_pipapo: fix range overlap detection") but that fix merely uncovers this bug. Before this commit, the wrong element is returned, but erronously reported as a full, identical duplicate. The root-cause is too early return in the avx2 match functions. When we process the last field, we should continue to process data until the entire input size has been consumed to make sure no stale bits remain in the map.

CVSS: 9.4 CRITICAL (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L
Weakness (CWE): CWE-480, CWE-20
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Modified
Record last updated: Oct 19, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from 7400b063969bdca4a06cd97f1294d765c8eecbe1 before f8c39983fc9c1a978c82e6f2df7bfba8a8561587; from 7400b063969bdca4a06cd97f1294d765c8eecbe1 before c7babe2f28b507e17f28e9f753b7caec72d4857f; 7400b063969bdca4a06cd97f1294d765c8eecbe1 builds before 1c43f0dd8691ddf8884793b481ddc7511cf593c3; from 7400b063969bdca4a06cd97f1294d765c8eecbe1 before fa4f1f52528c73989d820f32bfca06bec5afeece; 7400b063969bdca4a06cd97f1294d765c8eecbe1 builds before 3d53f9aafd469ae1ea27051e00f5b96ca1b55d52; 7400b063969bdca4a06cd97f1294d765c8eecbe1 builds before 07de44424bb7f17ef9357e8535df96d9e97c40cb; 7400b063969bdca4a06cd97f1294d765c8eecbe1 builds before 0abbc43f71d99baadeeba6fa3fe1c80b676f57ed; from 7400b063969bdca4a06cd97f1294d765c8eecbe1 before d3c0037ffe1273fa1961e779ff6906234d6cf53c	CNA record
Red Hat Red Hat Enterprise Linux 10 redhat:enterprise_linux	10.2	CISA ADP
Red Hat Red Hat Enterprise Linux 10.0 Extended Update Support redhat:enterprise_linux_eus	from 0:6.12.0-55.103.1.el10_0 not affected	CISA ADP
Red Hat Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions redhat:rhel_e4s	from 0:5.14.0-284.191.1.el9_2 not affected	CISA ADP
Red Hat Red Hat Enterprise Linux 9.6 Extended Update Support redhat:rhel_eus	from 0:5.14.0-570.138.1.el9_6 not affected	CISA ADP
Red Hat Red Hat OpenShift Container Platform 4.20 redhat:openshift	from 4.20.9.6.202609092300-0 not affected	CISA ADP
Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem siemens:simatic_s7_1500_tm_mfp_gnu_linux_subsystem (from the name)	all versions	CISA ADP
linux linux_kernel linux:linux_kernel	from 5.7 before 6.6.136; from 6.7 before 6.12.83; from 6.13 before 6.18.24; from 6.19 before 6.19.14; 7.0; 7.0; 7.0; 7.0; and 1 more ranges	NVD

References

References

https://git.kernel.org/stable/c/f8c39983fc9c1a978c82e6f2df7bfba8a8561587
https://git.kernel.org/stable/c/c7babe2f28b507e17f28e9f753b7caec72d4857f
https://git.kernel.org/stable/c/1c43f0dd8691ddf8884793b481ddc7511cf593c3
https://git.kernel.org/stable/c/fa4f1f52528c73989d820f32bfca06bec5afeece	patch
https://git.kernel.org/stable/c/3d53f9aafd469ae1ea27051e00f5b96ca1b55d52	patch
https://git.kernel.org/stable/c/07de44424bb7f17ef9357e8535df96d9e97c40cb	patch
https://git.kernel.org/stable/c/0abbc43f71d99baadeeba6fa3fe1c80b676f57ed	patch
https://git.kernel.org/stable/c/d3c0037ffe1273fa1961e779ff6906234d6cf53c	patch
https://access.redhat.com/errata/RHSA-2026:59723
https://access.redhat.com/errata/RHSA-2026:62568
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The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.