# CVE-2026-48840: exim4: Exim 4.88 before 4.99.4, in some proxy configurations, mishandles certain short payloads, leading to disclosure of un...

CVE-2026-48840 is fixed in 6 products on 1 platform, first by exim4 4.99.1-1ubuntu1.3, released May 29, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-48840
- Priority: Routine
- CVSS: 5.3 (medium)
- EPSS: 0.0026
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: May 29, 2026

## Description

Exim 4.88 before 4.99.4, in some proxy configurations, mishandles certain short payloads, leading to disclosure of uninitialized stack memory values to a client.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | exim4 Debian 12.15 (bookworm) | 4.96-15+deb12u10 | [DEBIAN-CVE-2026-48840](https://patchblox.com/security/data/fix/linux/debian-cve-2026-48840.md) | Jun 24, 2026 |
| Linux | exim4 Debian 13.5 (trixie) | 4.98.2-1+deb13u3 | [DEBIAN-CVE-2026-48840](https://patchblox.com/security/data/fix/linux/debian-cve-2026-48840.md) | Jun 24, 2026 |
| Linux | exim4 Debian 14 | 4.99.3-2 | [DEBIAN-CVE-2026-48840](https://patchblox.com/security/data/fix/linux/debian-cve-2026-48840.md) | Jun 24, 2026 |
| Linux | exim4 Ubuntu 18.04.6 LTS (bionic) | 4.90.1-1ubuntu1.10+esm6 | [exim4 4.90.1-1ubuntu1.10+esm6](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-exim4-4.90.1-1ubuntu1.10-esm6.md) | Jun 24, 2026 |
| Linux | exim4 Ubuntu 20.04 LTS (focal) | 4.93-13ubuntu1.12+esm1 | [exim4 4.93-13ubuntu1.12+esm1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-exim4-4.93-13ubuntu1.12-esm1.md) | Jun 24, 2026 |
| Linux | exim4 Ubuntu 22.04.1 LTS (jammy) | 4.95-4ubuntu2.9 | [exim4 4.95-4ubuntu2.9](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-exim4-4.95-4ubuntu2.9.md) | Jun 24, 2026 |
| Linux | exim4 Ubuntu 24.04.5 LTS (noble) | 4.97-4ubuntu4.6 | [exim4 4.97-4ubuntu4.6](https://patchblox.com/security/data/fix/linux/ubuntu-noble-exim4-4.97-4ubuntu4.6.md) | Jun 24, 2026 |
| Linux | exim4 Ubuntu 25.10 (questing) | 4.98.2-1ubuntu2.3 | [exim4 4.98.2-1ubuntu2.3](https://patchblox.com/security/data/fix/linux/ubuntu-questing-exim4-4.98.2-1ubuntu2.3.md) | Jun 24, 2026 |
| Linux | exim4 Ubuntu 26.04.1 LTS (resolute) | 4.99.1-1ubuntu1.3 | [exim4 4.99.1-1ubuntu1.3](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-exim4-4.99.1-1ubuntu1.3.md) | May 29, 2026 |
| Linux | exim4-base Ubuntu 18.04.6 LTS (bionic) | 4.90.1-1ubuntu1.10+esm6 | [exim4-base 4.90.1-1ubuntu1.10+esm6](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-exim4-base-4.90.1-1ubuntu1.10-esm6.md) | Jun 24, 2026 |
| Linux | exim4-base Ubuntu 20.04 LTS (focal) | 4.93-13ubuntu1.12+esm1 | [exim4-base 4.93-13ubuntu1.12+esm1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-exim4-base-4.93-13ubuntu1.12-esm1.md) | Jun 24, 2026 |
| Linux | exim4-base Ubuntu 22.04.1 LTS (jammy) | 4.95-4ubuntu2.9 | [exim4-base 4.95-4ubuntu2.9](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-exim4-base-4.95-4ubuntu2.9.md) | Jun 24, 2026 |
| Linux | exim4-base Ubuntu 24.04.5 LTS (noble) | 4.97-4ubuntu4.6 | [exim4-base 4.97-4ubuntu4.6](https://patchblox.com/security/data/fix/linux/ubuntu-noble-exim4-base-4.97-4ubuntu4.6.md) | Jun 24, 2026 |
| Linux | exim4-base Ubuntu 25.10 (questing) | 4.98.2-1ubuntu2.3 | [exim4-base 4.98.2-1ubuntu2.3](https://patchblox.com/security/data/fix/linux/ubuntu-questing-exim4-base-4.98.2-1ubuntu2.3.md) | Jun 24, 2026 |
| Linux | exim4-base Ubuntu 26.04.1 LTS (resolute) | 4.99.1-1ubuntu1.3 | [exim4-base 4.99.1-1ubuntu1.3](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-exim4-base-4.99.1-1ubuntu1.3.md) | May 29, 2026 |
| Linux | exim4-config Ubuntu 18.04.6 LTS (bionic) | 4.90.1-1ubuntu1.10+esm6 | [exim4-config 4.90.1-1ubuntu1.10+esm6](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-exim4-config-4.90.1-1ubuntu1.10-esm6.md) | Jun 24, 2026 |
| Linux | exim4-config Ubuntu 20.04 LTS (focal) | 4.93-13ubuntu1.12+esm1 | [exim4-config 4.93-13ubuntu1.12+esm1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-exim4-config-4.93-13ubuntu1.12-esm1.md) | Jun 24, 2026 |
| Linux | exim4-config Ubuntu 22.04.1 LTS (jammy) | 4.95-4ubuntu2.9 | [exim4-config 4.95-4ubuntu2.9](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-exim4-config-4.95-4ubuntu2.9.md) | Jun 24, 2026 |
| Linux | exim4-config Ubuntu 24.04.5 LTS (noble) | 4.97-4ubuntu4.6 | [exim4-config 4.97-4ubuntu4.6](https://patchblox.com/security/data/fix/linux/ubuntu-noble-exim4-config-4.97-4ubuntu4.6.md) | Jun 24, 2026 |
| Linux | exim4-config Ubuntu 25.10 (questing) | 4.98.2-1ubuntu2.3 | [exim4-config 4.98.2-1ubuntu2.3](https://patchblox.com/security/data/fix/linux/ubuntu-questing-exim4-config-4.98.2-1ubuntu2.3.md) | Jun 24, 2026 |
| Linux | exim4-config Ubuntu 26.04.1 LTS (resolute) | 4.99.1-1ubuntu1.3 | [exim4-config 4.99.1-1ubuntu1.3](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-exim4-config-4.99.1-1ubuntu1.3.md) | May 29, 2026 |
| Linux | exim4-daemon-heavy Ubuntu 18.04.6 LTS (bionic) | 4.90.1-1ubuntu1.10+esm6 | [exim4-daemon-heavy 4.90.1-1ubuntu1.10+esm6](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-exim4-daemon-heavy-4.90.1-1ubuntu1.10-esm6.md) | Jun 24, 2026 |
| Linux | exim4-daemon-heavy Ubuntu 20.04 LTS (focal) | 4.93-13ubuntu1.12+esm1 | [exim4-daemon-heavy 4.93-13ubuntu1.12+esm1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-exim4-daemon-heavy-4.93-13ubuntu1.12-esm1.md) | Jun 24, 2026 |
| Linux | exim4-daemon-heavy Ubuntu 22.04.1 LTS (jammy) | 4.95-4ubuntu2.9 | [exim4-daemon-heavy 4.95-4ubuntu2.9](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-exim4-daemon-heavy-4.95-4ubuntu2.9.md) | Jun 24, 2026 |
| Linux | exim4-daemon-heavy Ubuntu 24.04.5 LTS (noble) | 4.97-4ubuntu4.6 | [exim4-daemon-heavy 4.97-4ubuntu4.6](https://patchblox.com/security/data/fix/linux/ubuntu-noble-exim4-daemon-heavy-4.97-4ubuntu4.6.md) | Jun 24, 2026 |
| Linux | exim4-daemon-heavy Ubuntu 25.10 (questing) | 4.98.2-1ubuntu2.3 | [exim4-daemon-heavy 4.98.2-1ubuntu2.3](https://patchblox.com/security/data/fix/linux/ubuntu-questing-exim4-daemon-heavy-4.98.2-1ubuntu2.3.md) | Jun 24, 2026 |
| Linux | exim4-daemon-heavy Ubuntu 26.04.1 LTS (resolute) | 4.99.1-1ubuntu1.3 | [exim4-daemon-heavy 4.99.1-1ubuntu1.3](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-exim4-daemon-heavy-4.99.1-1ubuntu1.3.md) | May 29, 2026 |
| Linux | exim4-daemon-light Ubuntu 18.04.6 LTS (bionic) | 4.90.1-1ubuntu1.10+esm6 | [exim4-daemon-light 4.90.1-1ubuntu1.10+esm6](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-exim4-daemon-light-4.90.1-1ubuntu1.10-esm6.md) | Jun 24, 2026 |
| Linux | exim4-daemon-light Ubuntu 20.04 LTS (focal) | 4.93-13ubuntu1.12+esm1 | [exim4-daemon-light 4.93-13ubuntu1.12+esm1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-exim4-daemon-light-4.93-13ubuntu1.12-esm1.md) | Jun 24, 2026 |
| Linux | exim4-daemon-light Ubuntu 22.04.1 LTS (jammy) | 4.95-4ubuntu2.9 | [exim4-daemon-light 4.95-4ubuntu2.9](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-exim4-daemon-light-4.95-4ubuntu2.9.md) | Jun 24, 2026 |
| Linux | exim4-daemon-light Ubuntu 24.04.5 LTS (noble) | 4.97-4ubuntu4.6 | [exim4-daemon-light 4.97-4ubuntu4.6](https://patchblox.com/security/data/fix/linux/ubuntu-noble-exim4-daemon-light-4.97-4ubuntu4.6.md) | Jun 24, 2026 |
| Linux | exim4-daemon-light Ubuntu 25.10 (questing) | 4.98.2-1ubuntu2.3 | [exim4-daemon-light 4.98.2-1ubuntu2.3](https://patchblox.com/security/data/fix/linux/ubuntu-questing-exim4-daemon-light-4.98.2-1ubuntu2.3.md) | Jun 24, 2026 |
| Linux | exim4-daemon-light Ubuntu 26.04.1 LTS (resolute) | 4.99.1-1ubuntu1.3 | [exim4-daemon-light 4.99.1-1ubuntu1.3](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-exim4-daemon-light-4.99.1-1ubuntu1.3.md) | May 29, 2026 |
| Linux | eximon4 Ubuntu 18.04.6 LTS (bionic) | 4.90.1-1ubuntu1.10+esm6 | [eximon4 4.90.1-1ubuntu1.10+esm6](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-eximon4-4.90.1-1ubuntu1.10-esm6.md) | Jun 24, 2026 |
| Linux | eximon4 Ubuntu 20.04 LTS (focal) | 4.93-13ubuntu1.12+esm1 | [eximon4 4.93-13ubuntu1.12+esm1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-eximon4-4.93-13ubuntu1.12-esm1.md) | Jun 24, 2026 |
| Linux | eximon4 Ubuntu 22.04.1 LTS (jammy) | 4.95-4ubuntu2.9 | [eximon4 4.95-4ubuntu2.9](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-eximon4-4.95-4ubuntu2.9.md) | Jun 24, 2026 |
| Linux | eximon4 Ubuntu 24.04.5 LTS (noble) | 4.97-4ubuntu4.6 | [eximon4 4.97-4ubuntu4.6](https://patchblox.com/security/data/fix/linux/ubuntu-noble-eximon4-4.97-4ubuntu4.6.md) | Jun 24, 2026 |
| Linux | eximon4 Ubuntu 25.10 (questing) | 4.98.2-1ubuntu2.3 | [eximon4 4.98.2-1ubuntu2.3](https://patchblox.com/security/data/fix/linux/ubuntu-questing-eximon4-4.98.2-1ubuntu2.3.md) | Jun 24, 2026 |
| Linux | eximon4 Ubuntu 26.04.1 LTS (resolute) | 4.99.1-1ubuntu1.3 | [eximon4 4.99.1-1ubuntu1.3](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-eximon4-4.99.1-1ubuntu1.3.md) | May 29, 2026 |

---

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

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.