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Back to active CVEs
Medium · CVSS 5.9CVE-2025-9901

Libsoup: improper handling of http vary header in libsoup cachingCVE-2025-9901

Answer in brief

CVE-2025-9901 records a Medium severity (CVSS 5.9) vulnerability in Libsoup: improper handling of http vary header in libsoup caching. The current sources do not mark it as known exploited. The current feed maps Red Hat/libsoup (generic), Red Hat/libsoup3 (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 3, 2025Updated Oct 18, 2026Source checked Nov 3, 2026First seen by HOL Jun 25, 2026Material review Oct 18, 2026
Upstream Advisory

Key facts

Risk
Medium · CVSS 5.9
Exploitation
Not marked as known exploited
Affected software
2 mapped packages or products
Fix availability
Not reported

Why this deserves its current priority

CVSS is 5.9. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Red Hat/libsoup (generic), Red Hat/libsoup3 (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
PackageAffected rangeFixed version
Red Hat/libsoupgeneric*Not reported
Red Hat/libsoup3generic*Not reported

Recommended response

  1. 1Check inventory. Check lockfiles and deployed manifests for Red Hat/libsoup, Red Hat/libsoup3.
  2. 2Review the reported fix. Source-reported workaround: Mitigation for this issue is either not available or the currently available options do not meet Red Hat Product Security criteria comprising ease of use, deployment applicability to widespread installations, or stability. Administrators should apply vendor-supplied patches once they become available.

Evidence timeline and material changes

  1. Published upstream

    Sep 3, 2025

    Evidence: source:cvelist:source_dates:source-dates:record

  2. Source modified

    Oct 18, 2026

    Evidence: source:cvelist:source_dates:source-dates:record

  3. First seen by HOL

    Jun 25, 2026

Sources and claim methodology

  • Source referenceaccess.redhat.com
  • Source referencebugzilla.redhat.com
  • Source referencegitlab.gnome.org
Upstream source description

A flaw was found in libsoup’s caching mechanism, SoupCache, where the HTTP Vary header is ignored when evaluating cached responses. This header ensures that responses vary appropriately based on request headers such as language or authentication. Without this check, cached content can be incorrectly reused across different requests, potentially exposing sensitive user information. While the issue is unlikely to affect everyday desktop use, it could result in confidentiality breaches in proxy or multi-user environments.

Quoted source text, attributed separately from HOL analysis.

Related CVEs

  • Use of Cache Containing Sensitive Information in Elasticsearch Leading to Information DisclosureAlso CWE-524

Record context

Vulnerability class
Missing Auth
EPSS
Not reported
CWE IDs
CWE-524
Source
CVE List V5
Source checked
Nov 3, 2026
References
3 linked sources
Open source record