Medium [CVE-2025-4035] Libsoup: cookie domain validation bypass via uppercase characters in libsoup
This medium-severity Red Hat Linux advisory covers CVE-2025-4035 affecting Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7.
Aggregated and source-linked by VulniPulse. Data sources, validation and limitations.
VulniPulse record published
Summary
A flaw was found in libsoup. When handling cookies, libsoup clients mistakenly allow cookies to be set for public suffix domains if the domain contains at least two components and includes an uppercase character.
This bypasses public suffix protections and could allow a malicious website to set cookies for domains it does not own, potentially leading to integrity issues such as session fixation. Red Hat severity: Moderate — CVSS 4.3 (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N).
Weakness: CWE-178. Affected Red Hat products: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 6; Red Hat Enterprise Linux 7; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9.
Red Hat fixing advisory: RHSA-2025:8128.
Affected products named by the advisory: Red Hat package: libsoup3.
Is CVE-2025-4035 exploited?
No exploitation is reported in the sources VulniPulse tracks: CVE-2025-4035 is not in the CISA KEV catalog (checked ) and this advisory does not report exploitation. That is not proof the vulnerability cannot be exploited.
How do I fix CVE-2025-4035?
Upgrade to a fixed release named by Red Hat:
- libsoup3-0:3.6.5-3.el10_0.6
- RHSA-2025:8128
Confirm against the vendor advisory before you patch.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative. Check it before change work.
Official advisory · high-confidence parse· fetched 5 days ago·verify at source
- libsoup3-0:3.6.5-3.el10_0.6
- RHSA-2025:8128
Official advisory · high-confidence parse· fetched 5 days ago·verify at source
Mitigation
Upgrade to a fixed release: libsoup3-0:3.6.5-3.el10_0.6, RHSA-2025:8128. That is the remediation for this advisory.
The vendor advisory may list interim mitigations or workarounds not captured here. Review it before change work.
Official advisory · high-confidence parse· fetched 5 days ago·verify at source
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