# CVE-2025-4035: libsoup3: A flaw was found in libsoup

CVE-2025-4035 is fixed in 3 products on 1 platform, first by RHSA-2025:8128, released May 19, 2025. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2025-4035
- Priority: High
- CVSS: 7.5 (moderate)
- EPSS: 0.0054
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Apr 28, 2025

## Description

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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | libsoup3 RHEL 10 | 3.6.5-3.el10_0.6 | [RHSA-2025:8128](https://patchblox.com/security/data/fix/linux/rhsa-2025-8128.md) | May 19, 2025 |
| Linux | libsoup3 ol 10 | 0:3.6.5-3.el10_0.6 | [ELSA-2025-8128](https://patchblox.com/security/data/fix/linux/elsa-2025-8128.md) | Jun 26, 2025 |
| Linux | libsoup3 rocky 10 | 0:3.6.5-3.el10_0.6 | [RLSA-2025:8128](https://patchblox.com/security/data/fix/linux/rlsa-2025-8128.md) | Oct 3, 2025 |
| Linux | libsoup3-devel ol 10 | 0:3.6.5-3.el10_0.6 | [ELSA-2025-8128](https://patchblox.com/security/data/fix/linux/elsa-2025-8128.md) | Jun 26, 2025 |
| Linux | libsoup3-doc almalinux 10 | 3.6.5-3.el10_0.6 | [ALSA-2025:8128](https://patchblox.com/security/data/fix/linux/alsa-2025-8128.md) | May 26, 2025 |
| Linux | libsoup3-doc ol 10 | 0:3.6.5-3.el10_0.6 | [ELSA-2025-8128](https://patchblox.com/security/data/fix/linux/elsa-2025-8128.md) | Jun 26, 2025 |

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Data as of 2026-11-08T00:53:09Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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