# CVE-2026-94054 — Exim

> As of 2026-09-19, CVE-2026-94054 is a HIGH-severity vulnerability in Exim, CVSS v3.1 7, EPSS 0.2% (19.9th percentile). No Threadlinqs-tracked threat campaign has been attributed to CVE-2026-94054 as of 2026-09-19; the identifier is re-checked against the Threadlinqs threat corpus on every daily ingest.

**Last updated:** 2026-09-19

## What is CVE-2026-94054?

Exim before 4.100.1, when Proxy-Protocol is used with an attacker-controlled proxy, has an out-of-bounds write.

The record classifies CVE-2026-94054 under weakness class [CWE-787](https://intel.threadlinqs.com/cwe/CWE-787). Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on integrity. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 16 days ago.

## Severity and exploitation probability

- **CVSS v3.1 base score:** 7 — HIGH (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:L`)
- **EPSS (FIRST):** 0.2% probability of exploitation in the next 30 days, higher than 19.9% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 4.3/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-09-19

## Is CVE-2026-94054 being exploited?

It currently carries a trending score of 35 in the Threadlinqs vulnerability feed.

## Affected products and versions

- [Exim](https://intel.threadlinqs.com/vendors/exim): Exim

## How to fix CVE-2026-94054

No vendor patch reference has been recorded for CVE-2026-94054 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2026-94054

No threat campaign in the Threadlinqs corpus currently references CVE-2026-94054, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.

## Sources

Enriched from CVE.org, FIRST EPSS. Last verified by Threadlinqs on 2026-09-20.

**Other references**

- [lists.exim.org](https://lists.exim.org/lurker/message/20260918.121220.0f87338e.en.html)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-94054
Full detection coverage and IOCs for threats exploiting CVE-2026-94054 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp