CVE-2025-40063
- Published: 2025-10-28T12:15:40.730
- Last modified: 1761653740
In the Linux kernel, the following vulnerability has been resolved:
crypto: comp – Use same definition of context alloc and free ops
In commit 42d9f6c77479 (“crypto: acomp – Move scomp stream allocation
code into acomp”), the crypto_acomp_streams struct was made to rely on
having the alloc_ctx and free_ctx operations defined in the same order
as the scomp_alg struct. But in that same commit, the alloc_ctx and
free_ctx members of scomp_alg may be randomized by structure layout
randomization, since they are contained in a pure ops structure
(containing only function pointers). If the pointers within scomp_alg
are randomized, but those in crypto_acomp_streams are not, then
the order may no longer match. This fixes the problem by removing the
union from scomp_alg so that both crypto_acomp_streams and scomp_alg
will share the same definition of alloc_ctx and free_ctx, ensuring
they will always have the same layout.
Related CVE by CWE
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How to fix CVE-2025-40063
Description: In the Linux kernel, the following vulnerability has been resolved: crypto: comp – Use same definition of context alloc and free ops In commit 42d9f6c77479 (“crypto: acomp – Move scomp stream allocation code into acomp”), the crypto_acomp_streams struct was made to rely on having the alloc_ctx and free_ctx operations defined in the same order as […]
Exploit Difficulty: HARD
⏱️ Time to exploit: > 4 hours
🛠️ Required skills: Advanced security expertise
💰 Public exploits: Rare or not public
How to Fix:
- Check if you're running the affected product
- Update to the latest patched version
- If patching is not immediately possible: restrict network exposure, apply least-privilege access
- Test the fix in a staging environment first
- Review logs for signs of exploitation
- Monitor for IOCs (Indicators of Compromise)
- Enable automatic security updates
- Set up vulnerability monitoring
- Review and harden security configurations
Exploit Difficulty Assessment
Vulnerability Timeline
CVE details first published to NVD database
CVE details were updated
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Detection Rules & IOCs
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No vendor/product data available.