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CVE-2026-3904 Detail

Description

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 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.


Metrics

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CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
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References to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
http://www.openwall.com/lists/oss-security/2026/03/11/5 CVE
https://sourceware.org/bugzilla/show_bug.cgi?id=29863 GNU C Library
https://sourceware.org/git/?p=glibc.git;a=blob_plain;f=advisories/GLIBC-SA-2026-0004;hb=HEAD GNU C Library
https://sourceware.org/git/?p=glibc.git;a=commit;h=8804157ad9da39631703b92315460808eac86b0c GNU C Library
https://sourceware.org/git/?p=glibc.git;a=commit;h=b712be52645282c706a5faa038242504feb06db5 GNU C Library

Weakness Enumeration

CWE-ID CWE Name Source
CWE-366 Race Condition within a Thread GNU C Library  

Change History

3 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2026-3904
NVD Published Date:
03/11/2026
NVD Last Modified:
03/11/2026
Source:
GNU C Library