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GlibcFramework / library · Gnu

CVE-2025-5745

MEDIUM · 5.6 CVSS v3.1 Published 2025-06-05
Fix available
A fix is available. Upgrade to 2.40-136 / 2.41-57 or later.
See remediation →
65/100
Remediation priority · Elevated
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
The strncmp implementation optimized for the Power10 processor in the GNU C Library version 2.40 and later writes to vector registers v20 to v31 without saving contents from the caller (those registers are defined as non-volatile registers by the powerpc64le ABI), resulting in overwriting of its contents and potentially altering control flow of the caller, or leaking the input strings to the function to other parts of the program.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

The strncmp implementation optimized for Power10 processors in glibc 2.40+ writes to vector registers v20-v31 without preserving caller contents, violating the powerpc64le ABI which defines these as non-volatile registers. This can corrupt caller state, potentially alter control flow, or leak string data to other program parts.

MitigationUpgrade glibc to a version that properly saves/restores vector registers in the Power10 strncmp implementation, or avoid running affected code on powerpc64le systems until a patch is available.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
GlibcFramework / library
Affected:>= 2.40, < 2.40-136>= 2.41, < 2.41-57

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
Low

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check system architecture
    Run 'uname -m' or 'arch' to confirm the system is powerpc64le
    Affected if Architecture is not powerpc64le (the vulnerability only affects PowerPC 64-bit little-endian systems)
  2. Identify Power10 processor
    Check CPU model via 'cat /proc/cpuinfo' and look for 'POWER10' or a model number starting with 10 (e.g., PowerNV 10) in the 'model' or 'cpu' fields
    Affected if System is not running on Power10 hardware (the flawed strncmp optimization is Power10-specific)
  3. Determine installed glibc version
    Run 'ldd --version' or check /lib64/libc.so.6 for the version string; on distributions use 'rpm -q glibc' or 'dpkg -l libc6'
    Affected if glibc version is 2.40 through 2.40-135 inclusive, or 2.41 through 2.41-56 inclusive (versions outside these ranges are patched)
  4. Confirm strncmp usage in compiled code
    If possible, scan binaries/libraries linked on the system using 'nm -D' or 'objdump -T' to confirm they reference strncmp; note that any program using strncmp on affected systems is theoretically vulnerable
    Affected if The system runs any program that calls strncmp on the Power10 processor with an affected glibc version

A system is affected only if it is powerpc64le architecture, runs on Power10 hardware, and has glibc versions 2.40-2.40-135 or 2.41-2.41-56 installed.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 2.40-136 / 2.41-57 or later
Fixed in 2.40-1362.41-57
Interim mitigation

Upgrade glibc to a version that properly saves/restores vector registers in the Power10 strncmp implementation, or avoid running affected code on powerpc64le systems until a patch is available.

Recommended fix High confidence

glibc 2.40-136 or later, or 2.41-57 or later, or latest stable (2.42+)

  1. Identify all systems and applications using glibc version 2.40 through 2.40-135 or 2.41 through 2.41-56 on Power10 (powerpc64le) architecture
  2. Update glibc to version 2.40-136 or later for the 2.40 release line
  3. Alternatively, update glibc to version 2.41-57 or later for the 2.41 release line
  4. Alternatively, update to the latest stable glibc release (2.42 or later) which contains the fix
  5. Rebuild and redeploy any statically linked applications that include the vulnerable glibc version
  6. Reboot or restart affected services to ensure the new glibc is loaded
Caveat Minor - standard library update; standard strncmp behavior remains unchanged

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Glibc Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,500
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-5745 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data