# libundertow-java security updates

Patch Radar has 5 security fixes for libundertow-java, closing 5 CVEs. The newest is libundertow-java 1.4.23-3ubuntu0.1~esm1 (1.4.23-3ubuntu0.1~esm1), released January 7, 2026.

- Web page: https://patchblox.com/security/product/linux/libundertow-java
- Platform: Linux
- Supported: yes

## Security fixes, newest first

| Fix | Released | Fixed in | Priority | CVEs | Exploited |
|---|---|---|---|---:|---:|
| [libundertow-java 1.4.23-3ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libundertow-java-1.4.23-3ubuntu0.1-esm1.md) | Jan 7, 2026 | Ubuntu 18.04.6 LTS (bionic) 1.4.23-3ubuntu0.1~esm1 | High | 1 | 0 |
| [libundertow-java 2.0.29-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libundertow-java-2.0.29-1ubuntu0.1-esm1.md) | Jan 7, 2026 | Ubuntu 20.04 LTS (focal) 2.0.29-1ubuntu0.1~esm1 | High | 1 | 0 |
| [libundertow-java 2.2.16-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libundertow-java-2.2.16-1ubuntu0.1-esm1.md) | Jan 7, 2026 | Ubuntu 22.04.1 LTS (jammy) 2.2.16-1ubuntu0.1~esm1 | High | 1 | 0 |
| [libundertow-java 2.3.8-2ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libundertow-java-2.3.8-2ubuntu0.1-esm1.md) | Jan 7, 2026 | Ubuntu 24.04.5 LTS (noble) 2.3.8-2ubuntu0.1~esm1 | High | 1 | 0 |
| [libundertow-java 2.0.23-1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libundertow-java-2.0.23-1.md) | Jul 25, 2019 | Ubuntu 20.04 LTS (focal) 2.0.23-1 | Routine | 4 | 0 |

---

Data as of 2026-11-07T00:32:44Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo