Raw vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HSummary
CVE-2026-3904 is a medium-severity Race Condition within a Thread (CWE-366) vulnerability in Gnu Glibc. Its CVSS base score is 6.2 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 4th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
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-2026-11160
Vulnerability Data
Calling NSS-backed functions that support caching via nscd may call the nscd client side code and in the GNU C Library version 2.36 under high load on x86_64 systems, the client may call memcmp on inputs that are concurrently modified…
more
by other processes or threads and crash. The nscd client in the GNU C Library uses the memcmp function with inputs that may be concurrently modified by another thread, potentially resulting in spurious cache misses, which in itself is not a security issue. However in the GNU C Library version 2.36 an optimized implementation of memcmp was introduced for x86_64 which could crash when invoked with such undefined behaviour, turning this into a potential crash of the nscd client and the application that uses it. This implementation was backported to the 2.35 branch, making the nscd client in that branch vulnerable as well. Subsequently, the fix for this issue was backported to all vulnerable branches in the GNU C Library repository. It is advised that distributions that may have cherry-picked the memcpy SSE2 optimization in their copy of the GNU C Library, also apply the fix to avoid the potential crash in the nscd client.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V15.4.2V15.4.3V17.2.6
Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation can include concurrency and stress testing that finds race conditions after they have been coded.
Requiring documented development standards and tools can mandate use of safe concurrency patterns that avoid introducing races.
Security engineering principles include requirements for synchronization primitives and thread-safe design that stop race conditions from being introduced.
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 practices directly require synchronization primitives and concurrency analysis that prevent intra-thread race conditions.
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 can detect race conditions through concurrency and stress testing.
Secure development lifecycle includes concurrency and synchronization practices that reduce race conditions.
Application security requirements can mandate thread-safety and locking controls.
Secure architecture principles address concurrent access and resource synchronization.
Secure coding standards directly require proper synchronization primitives to prevent race conditions.
Change management can introduce or remove synchronization flaws during updates.