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CVE-2025-9901

Libsoup: improper handling of http vary header in libsoup caching

Products / packages Red Hat Enterprise Linux 10 · Red Hat Enterprise Linux 6 · Red Hat Enterprise Linux 7 · 2 more

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Severity and exploitation

Not in CISA KEV

KEV coverage does not rule out exploitation.

KEV checked 15/11/2026, 02:25:31 UTC
redhat · CVSS:3.1 · 5.9
Assessment vectorCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Severity

medium5.9

CVSS measures technical severity, not the likelihood of an attack.

Known exploitation

Not listed in the checked CISA KEV catalog

Absence from CISA KEV does not rule out attacks.

Public exploit

Not established by this record

Missing evidence does not mean no public exploit exists.

Remediation

Source guidance available

Review the recorded instructions. Guidance may be a workaround rather than a fixed version.

What this means

Libsoup's caching mechanism ignores the HTTP Vary header, potentially exposing sensitive user information in proxy or multi-user environments. The issue affects Red Hat Enterprise Linux 7, 8, 9, and 10. Confidentiality breaches may occur due to incorrect reuse of cached content.

Summarized by @cf/meta/llama-3.3-70b-instruct-fp8-fast. Verify details against the original sources.

Attack conditions

No attack-condition excerpt has been identified here. Review the full source description and references for authentication, network access, and configuration requirements.

Review supporting sources →

Affected versions

Check the exact model, release, and any platform requirements against your installation.

Red Hat · redhat

Red Hat Enterprise Linux 10

0 ranges
redhat version evidence

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affected

unaffected

unknown

Other versions: affected

Product identifiers (CPE)cpe:/a:redhat:enterprise_linux:10

Red Hat · redhat

Red Hat Enterprise Linux 6

0 ranges
redhat version evidence

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affected

unaffected

unknown

Other versions: unknown

Product identifiers (CPE)cpe:/o:redhat:rhel_els:6

Red Hat · redhat

Red Hat Enterprise Linux 7

0 ranges
redhat version evidence

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affected

unaffected

unknown

Other versions: affected

Product identifiers (CPE)cpe:/o:redhat:rhel_els:7

Red Hat · redhat

Red Hat Enterprise Linux 8

0 ranges
redhat version evidence

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affected

unaffected

unknown

Other versions: affected

Product identifiers (CPE)cpe:/a:redhat:enterprise_linux:8

Red Hat · redhat

Red Hat Enterprise Linux 9

0 ranges
redhat version evidence

Compare with this publisher’s ranges. This does not inspect your installation.

affected

unaffected

unknown

Other versions: affected

Product identifiers (CPE)cpe:/a:redhat:enterprise_linux:9
Automatic dependency matching is unavailable for this record. Use the product evidence and publisher’s instructions to check your installation.

What to do

Compare your installed product and version with the affected versions above. A matching product name alone does not confirm exposure.

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.

redhat guidance ↗

cve.new guidance unless attributed to a publisher. This page does not inspect your installation.

Public exploit evidence

No public exploit reference is identified in the imported evidence. This is not a claim that no exploit exists.

Original source description

Read the full publisher 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.

References

3 sources
access.redhat.com/security/cve/CVE-2025-9901
Security advisoryredhat
bugzilla.redhat.com/show_bug.cgi
Source referenceredhat
gitlab.gnome.org/GNOME/libsoup/-/issues/453
Source referenceredhat

Inside the record

Evidence available

Package identity · not supplied
Version evidence · not supplied
Remediation guidance
Weakness classification
Additional publishers

Describes the evidence in this view, not whether the product is safe.

Original records

CVE-2025-9901

View the latest unmodified CVE JSON from the official source. It may be newer than this imported page.

cve.new JSON →

Underlying weaknesses

The source’s classification of what caused the vulnerability.

CWE-524 ↗

Use of Cache Containing Sensitive Information

redhat

Related →
Contributing organizations · 2
redhat

Assigning organization

2026-11-05
CISA-ADP

Additional data publisher

2025-09-03

Timeline

All times UTC

  1. Advisory published

    Publication date supplied by the source.

  2. Source updated

    Latest modification date supplied by the source.

  3. Last imported by cve.new

    Latest catalog import, not the date we first saw this advisory.

What changed

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Large field values are marked as truncated previews. Original source snapshots remain retained.