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Out-of-bounds ReadWeakness · CWE-125

CVE-2025-11021

HIGH · 7.5 CVSS v3.1 Published 2025-09-26
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
84/100
Remediation priority · High
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
A flaw was found in the cookie date handling logic of the libsoup HTTP library, widely used by GNOME and other applications for web communication. When processing cookies with specially crafted expiration dates, the library may perform an out-of-bounds memory read. This flaw could result in unintended disclosure of memory contents, potentially exposing sensitive information from the process using libsoup.

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 confidence

libsoup HTTP library has an out-of-bounds read vulnerability in its cookie date handling logic. When processing cookies with specially crafted expiration dates, the library can read beyond allocated memory boundaries, potentially exposing sensitive process memory contents to attackers.

MitigationUpdate libsoup to the patched version once available. Until then, restrict exposure to untrusted HTTP servers and monitor for unusual application behavior.

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
High
Integrity
None
Availability
None

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

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. Identify if libsoup is installed
    On Debian-based systems: dpkg -l | grep libsoup. On Red Hat-based systems: rpm -qa | grep libsoup. On general Linux: find /usr -name "*libsoup*" 2>/dev/null
    Affected if libsoup is not present on the system, the vulnerability does not apply
  2. Determine the installed libsoup version
    Run: pkg-config --modversion libsoup-3.0 (for libsoup3) or pkg-config --modversion libsoup-2.4 (for libsoup2). If pkg-config is unavailable, check the package manager: apt list --installed 2>/dev/null | grep libsoup or rpm -q libsoup
    Affected if the installed version matches or predates the vulnerable release (compare against the fixed version once published)
  3. Verify if the application uses libsoup HTTP client functionality
    Inspect application dependencies: ldd /path/to/application | grep libsoup, or review application documentation/configuration to confirm it uses libsoup for HTTP requests
    Affected if the application does not link to or use libsoup, the cookie handling code is not reached
  4. Determine if the application processes cookies from untrusted sources
    Review application configuration and network exposure: check if the application connects to untrusted HTTP servers, processes third-party cookies, or handles user-supplied HTTP responses. Inspect any proxy or intercept configurations that could inject malicious cookies
    Affected if the application only processes cookies from trusted internal servers and does not handle external HTTP responses, exploitation is not possible

You are affected if a vulnerable version of libsoup is installed AND an application using its HTTP client processes cookies from untrusted or external sources.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Update libsoup to the patched version once available. Until then, restrict exposure to untrusted HTTP servers and monitor for unusual application behavior.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA3.0 h
21.0 hours of engineering $3,680
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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-2025-11021 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
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