Linux kernel AppArmor verify_header memory leak
CVE-2026-23403 is a Linux kernel vulnerability in the AppArmor policy-unpacking path, specifically in the verify_header function. During unpacking of multiple profiles, verify_header incorrectly set *ns = NULL on every call. As a result, a namespace string allocated during a previous iteration could be leaked when subsequent profiles were processed. The same logic error also broke namespace consistency checking, because the comparison logic always observed *ns as NULL. The upstream fix removes the erroneous reassignment in verify_header; the caller, aa_unpack, already initializes *ns to NULL once before entering the loop, which is the intended behavior.
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Impact
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Mitigation
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Remediation
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*ns = NULL assignment from verify_header. Vendor-fixed package versions cited in the provided content include, for example: kernel-default >= 5.14.21-150400.24.219.1 for multiple SLES 15 SP4 branches, >= 5.14.21-150500.55.166.1 for multiple SLES 15 SP5 branches, >= 6.4.0-150600.23.112.1 for multiple SLES 15 SP6 branches, >= 6.4.0-150700.53.55.1 for multiple SLES 15 SP7 branches, and >= 6.12.0-160000.33.1 for SLES 16.0 / SUSE Linux Micro 6.2 / openSUSE Leap 16.0 related releases. Use the vendor advisory applicable to the deployed distribution and reboot into the updated kernel.Exploits
No public exploits tracked yet. Mallory keeps watching.
No public exploit code observed for this vulnerability.
Affected products & vendors
Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.
Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
Recent activity
3 sources tracked across advisories and community write-ups. News coverage will land here when it surfaces.
No news coverage yet. Advisories and community discussion only.
The version that knows your environment.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.