Medium 5.5Published May 6, 2026

CVE-2026-43089xfrm_user: fix info leak in build_mapping()

Updated under an hour ago (Oct 26, 2026, 2:50 PM ET)

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No exploitation reported and no EPSS estimate yet.

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Exploited in the last 30 days

In the Linux kernel, the following vulnerability has been resolved: xfrm_user: fix info leak in build_mapping() struct xfrm_usersa_id has a one-byte padding hole after the proto field, which ends up never getting set to zero before copying out to userspace. Fix that up by zeroing out the whole structure before setting individual variables.

CVSS: 5.5 MEDIUM (v3.1, NVD)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): Not given
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 14, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from 3a2dfbe8acb154905fdc2fd03ec56df42e6c4cc4 before 521385cbd50ca9474396d88462fcdfa6489685d9; from 3a2dfbe8acb154905fdc2fd03ec56df42e6c4cc4 before c2779ae9a3e5a044e5ccd564681511bbbcc5fc0f; from 3a2dfbe8acb154905fdc2fd03ec56df42e6c4cc4 before 72a8de41c3eb4dcf22bf3b674ea38fb2f75d6f32; from 3a2dfbe8acb154905fdc2fd03ec56df42e6c4cc4 before d3125c541a96fb3c0fc7210112684baf22b6c24d; from 3a2dfbe8acb154905fdc2fd03ec56df42e6c4cc4 before 5a1a4b049ddde41466ccac0daeec326254b133f2; from 3a2dfbe8acb154905fdc2fd03ec56df42e6c4cc4 before f779a6b6cdb6e12baa0663063ac59ab2a8f20c0c; from 3a2dfbe8acb154905fdc2fd03ec56df42e6c4cc4 before 700c9622b23c33b5933e6dcea816492c064e4e10; 3a2dfbe8acb154905fdc2fd03ec56df42e6c4cc4 builds before 1beb76b2053b68c491b78370794b8ff63c8f8c02	CNA record
Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518_4_pn_dp_mfp (from the name)	from V3.1.6	CISA ADP
Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518f_4_pn_dp_mfp (from the name)	from V3.1.6	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
Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP siemens:siplus_s7_1500_cpu_1518_4_pn_dp_mfp (from the name)	from V3.1.6	CISA ADP
linux linux_kernel linux:linux_kernel	from 2.6.29.1 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 3 more ranges	NVD

References

References

https://git.kernel.org/stable/c/521385cbd50ca9474396d88462fcdfa6489685d9
https://git.kernel.org/stable/c/c2779ae9a3e5a044e5ccd564681511bbbcc5fc0f
https://git.kernel.org/stable/c/72a8de41c3eb4dcf22bf3b674ea38fb2f75d6f32
https://git.kernel.org/stable/c/d3125c541a96fb3c0fc7210112684baf22b6c24d	patch
https://git.kernel.org/stable/c/5a1a4b049ddde41466ccac0daeec326254b133f2	patch
https://git.kernel.org/stable/c/f779a6b6cdb6e12baa0663063ac59ab2a8f20c0c	patch
https://git.kernel.org/stable/c/700c9622b23c33b5933e6dcea816492c064e4e10	patch
https://git.kernel.org/stable/c/1beb76b2053b68c491b78370794b8ff63c8f8c02	patch
https://cert-portal.siemens.com/productcert/html/ssa-019113.html
https://cert-portal.siemens.com/productcert/html/ssa-457936.html
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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.