CVE-2026-38639
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 · uneditedAn issue in the parse_month function (/time/strptime.rs) of relibc commit ab6a2e allows attackers to cause a Denial of Service (DoS) via parsing a crafted input.
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 · moderate confidenceA denial of service vulnerability exists in the parse_month function in relibc's time/strptime.rs. By providing a crafted input to this time parsing function, an attacker can cause the application to become unresponsive or crash, likely due to an infinite loop, excessive resource consumption, or panic in the parsing logic.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
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
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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 checksWork through these to decide whether this CVE applies to you.
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Identify if relibc is in useSearch for relibc library files or check application dependencies for the relibc crate. Look for strings or symbols referencing 'relibc' in binaries or check Cargo.lock files if the application is Rust-based.Affected if relibc is present as a dependency or linked library in the environment
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Determine the installed relibc versionCheck the version of relibc by examining Cargo.lock, cargo tree output, or library metadata. Compare against any known patched version or commit ab6a2e.Affected if The relibc version is older than the patched version (post-commit ab6a2e) or version cannot be determined
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Verify strptime or time parsing functions are being calledMonitor or trace application execution for calls to strptime, strftime, or other time parsing functions from relibc. Check for any user-controlled input being passed to time parsing routines.Affected if The application uses strptime or related time parsing functions with external input
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Inspect parse_month function implementationIf source code is accessible, examine the time/strptime.rs file for the parse_month function. Look for missing input validation or bounds checking on month string parsing.Affected if The parse_month function lacks proper bounds checking or input validation for month strings
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Test for DoS condition with crafted month inputIf testing is safe to perform in a non-production environment, provide malformed month strings (e.g., excessively long strings, null bytes, or invalid month formats) to time parsing functions and observe for infinite loops, excessive CPU consumption, or crashes.Affected if Application becomes unresponsive, hangs, or crashes when processing crafted month input in time parsing functions
A user is affected if they are running an application that uses a vulnerable version of relibc (prior to the patch at commit ab6a2e) and that application processes time/date strings via strptime or related parsing functions.
Generated from the published advisory. Verify against your own configuration.
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.
From vendor dataUpdate or patch relibc to a version after commit ab6a2e that addresses the parse_month vulnerability. Input validation and bounds checking should be implemented in the parsing logic to prevent malformed month strings from triggering the DoS condition.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-38639 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-38639 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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