# CVE-2023-4639: undertow: A flaw was found in Undertow, which incorrectly parses cookies with certain value-delimiting characters in incoming r...

CVE-2023-4639 is fixed in undertow on 1 platform, first by CVE-2023-4639, released November 17, 2024. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2023-4639
- Priority: High
- CVSS: 7.4 (high)
- EPSS: 0.0109
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Nov 17, 2024

## Description

A flaw was found in Undertow, which incorrectly parses cookies with certain value-delimiting characters in incoming requests. This issue could allow an attacker to construct a cookie value to exfiltrate HttpOnly cookie values or spoof arbitrary additional cookie values, leading to unauthorized data access or modification. The main threat from this flaw impacts data confidentiality and integrity.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | undertow Debian 13.5 (trixie) | 2.3.18-1 | [CVE-2023-4639](https://patchblox.com/security/data/fix/linux/cve-2023-4639.md) | Nov 17, 2024 |
| Linux | undertow Debian 14 | 2.3.18-1 | [DEBIAN-CVE-2023-4639](https://patchblox.com/security/data/fix/linux/debian-cve-2023-4639.md) | Nov 17, 2024 |

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Data as of 2026-11-08T06:59:42Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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