CVE-2025-21996
Linux Kernel 3.15 – 5.4.292
Raw vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2025-21996 is a medium-severity Use of Uninitialized Resource (CWE-908) vulnerability in Linux Linux Kernel. Its CVSS base score is 5.5 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique OS Credential Dumping (T1003); ranked at the 11th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SA-15 (Development Process, Standards, and Tools) — see the control section below for these in your framework.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-9590
Vulnerability Data
In the Linux kernel, the following vulnerability has been resolved: drm/radeon: fix uninitialized size issue in radeon_vce_cs_parse() On the off chance that command stream passed from userspace via ioctl() call to radeon_vce_cs_parse() is weirdly crafted and first command to execute…
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is to encode (case 0x03000001), the function in question will attempt to call radeon_vce_cs_reloc() with size argument that has not been properly initialized. Specifically, 'size' will point to 'tmp' variable before the latter had a chance to be assigned any value. Play it safe and init 'tmp' with 0, thus ensuring that radeon_vce_cs_reloc() will catch an early error in cases like these. Found by Linux Verification Center (linuxtesting.org) with static analysis tool SVACE. (cherry picked from commit 2d52de55f9ee7aaee0e09ac443f77855989c6b68)
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation (including static analysis) can find uses of uninitialized resources after they are coded.
Requiring documented development standards and tools can mandate initialization checks and safe patterns that stop the weakness from being introduced.
Engineering principles can require explicit resource initialization before use, structurally avoiding uninitialized access.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure SDLC activities such as static analysis and code review directly prevent use of uninitialized resources while also addressing many other weaknesses.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing in development and acceptance can detect uninitialized resource usage through dynamic analysis and fuzzing.
Secure development life cycle mandates initialization checks and static analysis that can catch uninitialized resource use.
Application security requirements can specify mandatory initialization of variables and resources before use.
Secure system architecture and engineering principles include defensive coding practices that prevent use of uninitialized memory or objects.
Secure coding standards directly require explicit initialization of all variables and resources, substantially mitigating CWE-908.