# CVE-2025-11678: libwebsockets-evlib-ev: Stack-based Buffer Overflow in lws_adns_parse_label in warmcat libwebsockets allows, when the LWS_WITH_SYS_ASYNC_DNS...

CVE-2025-11678 is fixed in 8 products on 1 platform, first by libwebsockets-evlib-ev 4.3.3-1.1ubuntu0.1~esm1, released October 20, 2025. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2025-11678
- Priority: Routine
- CVSS: n/a (Medium)
- EPSS: 0.0029
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Oct 20, 2025

## Description

Stack-based Buffer Overflow in lws_adns_parse_label in warmcat libwebsockets allows, when the LWS_WITH_SYS_ASYNC_DNS flag is enabled during compilation, to overflow the label_stack, when the attacker is able to sniff a DNS request in order to craft a response with a matching id containing a label longer than the maximum.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | libwebsockets Debian 13.5 (trixie) | 4.3.5-1+deb13u1 | [DEBIAN-CVE-2025-11678](https://patchblox.com/security/data/fix/linux/debian-cve-2025-11678.md) | Oct 20, 2025 |
| Linux | libwebsockets Debian 14 | 4.3.5-3 | [DEBIAN-CVE-2025-11678](https://patchblox.com/security/data/fix/linux/debian-cve-2025-11678.md) | Oct 20, 2025 |
| Linux | libwebsockets-evlib-ev Ubuntu 24.04.5 LTS (noble) | 4.3.3-1.1ubuntu0.1~esm1 | [libwebsockets-evlib-ev 4.3.3-1.1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libwebsockets-evlib-ev-4.3.3-1.1ubuntu0.1-esm1.md) | Oct 20, 2025 |
| Linux | libwebsockets-evlib-glib Ubuntu 24.04.5 LTS (noble) | 4.3.3-1.1ubuntu0.1~esm1 | [libwebsockets-evlib-glib 4.3.3-1.1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libwebsockets-evlib-glib-4.3.3-1.1ubuntu0.1-esm1.md) | Oct 20, 2025 |
| Linux | libwebsockets-evlib-uv Ubuntu 24.04.5 LTS (noble) | 4.3.3-1.1ubuntu0.1~esm1 | [libwebsockets-evlib-uv 4.3.3-1.1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libwebsockets-evlib-uv-4.3.3-1.1ubuntu0.1-esm1.md) | Oct 20, 2025 |
| Linux | libwebsockets-test-server Ubuntu 22.04.1 LTS (jammy) | 4.0.20-2ubuntu1.1 | [libwebsockets-test-server 4.0.20-2ubuntu1.1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libwebsockets-test-server-4.0.20-2ubuntu1.1.md) | Oct 20, 2025 |
| Linux | libwebsockets-test-server Ubuntu 24.04.5 LTS (noble) | 4.3.3-1.1ubuntu0.1~esm1 | [libwebsockets-test-server 4.3.3-1.1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libwebsockets-test-server-4.3.3-1.1ubuntu0.1-esm1.md) | Oct 20, 2025 |
| Linux | libwebsockets-test-server-common Ubuntu 22.04.1 LTS (jammy) | 4.0.20-2ubuntu1.1 | [libwebsockets-test-server-common 4.0.20-2ubuntu1.1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libwebsockets-test-server-common-4.0.20-2ubuntu1.1.md) | Oct 20, 2025 |
| Linux | libwebsockets-test-server-common Ubuntu 24.04.5 LTS (noble) | 4.3.3-1.1ubuntu0.1~esm1 | [libwebsockets-test-server-common 4.3.3-1.1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libwebsockets-test-server-common-4.3.3-1.1ubuntu0.1-esm1.md) | Oct 20, 2025 |
| Linux | libwebsockets16 Ubuntu 22.04.1 LTS (jammy) | 4.0.20-2ubuntu1.1 | [libwebsockets16 4.0.20-2ubuntu1.1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libwebsockets16-4.0.20-2ubuntu1.1.md) | Oct 20, 2025 |
| Linux | libwebsockets19t64 Ubuntu 24.04.5 LTS (noble) | 4.3.3-1.1ubuntu0.1~esm1 | [libwebsockets19t64 4.3.3-1.1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libwebsockets19t64-4.3.3-1.1ubuntu0.1-esm1.md) | Oct 20, 2025 |

---

Data as of 2026-11-09T07:25:28Z 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

Free to use with attribution: show "Data: Patchblox Patch Radar" with a link to https://patchblox.com/security/patch-radar. Terms, including what needs a written agreement: https://patchblox.com/security/patch-radar/use-the-data

Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.