CVE-2025-40063 | crypto: comp - Use same definition of context alloc and free ops

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.

Published: 2025-10-28 Last update: 2026-04-15 Assigner: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Conclusion & alert: CVE-2025-40063 is rated Low Risk (3.4/100): low exploitation likelihood (EPSS 0.02%). Mandatory action: Low composite risk—no urgent action required; patch on your normal maintenance cycle and revisit priority if CVSS or EPSS increases.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2025-40063

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-10-28 0.02%

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-40063

CVSS metrics for this CVE.

No CVSS data in dataset for this CVE.

Weakness enumeration for CVE-2025-40063

OS Trackers for CVE-2025-40063

vendor priority summary link
debian unimportant CVE-2025-40063 unimportant priority: Debian including 1 source packages (linux), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2025-40063
redhat medium https://access.redhat.com/security/cve/CVE-2025-40063
suse medium CVE-2025-40063 severity moderate: SUSE including 30 source package names (cluster-md-kmp-default, dlm-kmp-default, …), 273 product×package rows across 54 product lines (SLES-LTSS-TERADATA 15 SP2, SUSE Linux Enterprise High Availability Extension 15 SP7, … (54 product lines)): Known Not Affected 269, Fixed 4. https://www.suse.com/security/cve/CVE-2025-40063/
ubuntu medium CVE-2025-40063 medium priority: Ubuntu including 157 source packages (linux, linux-allwinner-5.19, …), 1405 status rows across 9 suites (bionic, focal, jammy, noble, plucky, questing, trusty, upstream, xenial): DNE 1010, ignored 159, not-affected 136, released 98, needed 2. https://ubuntu.com/security/CVE-2025-40063

Affected software / configurations for CVE-2025-40063

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2025-40063

cvelogic Threat Intelligence