What is CVE-2026-23403?
In the Linux kernel, the following vulnerability has been resolved: apparmor: fix memory leak in verify_header The function sets `*ns = NULL` on every call, leaking the namespace string allocated in previous iterations when multiple profiles are unpacked. This also breaks namespace consistency checking since *ns is always NULL when the comparison is made. Remove the incorrect assignment. The caller (aa_unpack) initializes *ns to NULL once before the loop, which is sufficient.
The record classifies CVE-2026-23403 under weakness class CWE-401. Its CVSS v3 base vector states that the flaw requires local access to the host, needs low-privilege credentials, needs no user interaction, and has high impact on availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 207 days ago.
Severity and exploitation probability
- CVSS v3.1 base score
- 5.5 — MEDIUM
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - EPSS (FIRST)
- 0.1% probability of exploitation in the next 30 days, higher than 6.6% of all scored CVEs
- CISA KEV
- Not listed in the CISA Known Exploited Vulnerabilities catalog
- Threadlinqs priority
- 3/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- Published
- 2026-04-01, last modified 2026-05-11
Is CVE-2026-23403 being exploited?
It currently carries a trending score of 7 in the Threadlinqs vulnerability feed.
Affected products and versions
- Linux: Linux
How to fix CVE-2026-23403
The record marks a vendor fix as available for CVE-2026-23403. Patch reference: https://git.kernel.org/stable/c/42fd831abfc15d0643c14688f0522556b347e7e6. Apply the vendor fix referenced above to every affected product listed in this record, then confirm the running version against the vendor advisory.
Threat activity tracking CVE-2026-23403
1 tracked threat in the Threadlinqs corpus references CVE-2026-23403, either in the campaign’s CVE list or as an indicator on the campaign record.
Sources
Enriched from CVE.org, NVD, FIRST EPSS, GitHub Security Advisories. Last verified by Threadlinqs on . This product uses the NVD API but is not endorsed or certified by the NVD.
Other references
- git.kernel.org
- git.kernel.org (6b79abcb3c985e153fcf9d395e1d4336081aabc2)
- git.kernel.org (bcf82c0c5a8b383fd2d5d8f3fd880cdcab2ac557)
- git.kernel.org (663ce34786e759ebcbeb3060685c20bcc886d51a)
- git.kernel.org (786e2c2a87d9c505f33321d1fd23a176aa8ddeb1)
Showing 5 of 8 recorded references.