CVE-2025-46420
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 · uneditedA flaw was found in libsoup. It is vulnerable to memory leaks in the soup_header_parse_quality_list() function when parsing a quality list that contains elements with all zeroes.
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 confidenceA memory leak vulnerability exists in libsoup's soup_header_parse_quality_list() function when parsing quality list headers that contain elements with all zeroes. The function fails to properly deallocate memory for these elements, leading to gradual memory exhaustion during repeated parsing operations.
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
- Required
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/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 libsoup installation and versionRun 'pkg-config --modversion libsoup-3.0' or 'dpkg -l | grep libsoup' (Debian) / 'rpm -qa | grep libsoup' (RHEL) to find the installed libsoup versionAffected if The installed version is older than the patched version and processes HTTP quality list headers
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Detect libsoup-dependent applicationsRun 'ldd /path/to/application | grep libsoup' or check package dependencies to identify programs using libsoupAffected if Applications linked against libsoup handle HTTP requests with Accept, Accept-Encoding, or similar quality list headers
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Identify header processing behaviorReview application code or configuration for HTTP client usage that processes quality values (Accept, Accept-Encoding, Accept-Language headers)Affected if The application processes HTTP responses containing quality list headers from servers
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Monitor for memory growthObserve memory usage of libsoup-consuming processes over time using 'ps aux' or memory profiling tools during sustained HTTP activityAffected if Memory usage steadily increases during repeated HTTP transactions involving quality list headers
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Verify quality list parsing occursEnable libsoup debug logging (SOUP_DEBUG) or network tracing to confirm quality list headers are being parsedAffected if The environment processes HTTP headers that trigger soup_header_parse_quality_list() with all-zero quality values
You are affected if libsoup is installed and any application using it processes HTTP quality list headers that could contain elements with all-zero quality values, causing memory to accumulate over repeated operations.
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 libsoup to the patched version when available. Until then, implement input validation to filter or reject quality list elements containing all-zero values before they reach the vulnerable parsing function.
- Consultation3.0 h
- Implementation6.0 h
- Testing4.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2025-46420 — 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-2025-46420 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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