What is CVE-2026-45185?
Exim before 4.99.3, in certain GnuTLS configurations, has a remotely reachable use-after-free in the BDAT body parsing path. It is triggered when a client sends a TLS close_notify mid-body during a CHUNKING transfer, followed by a final cleartext byte on the same TCP connection. This can lead to heap corruption. An unauthenticated network attacker exploiting this vulnerability could execute arbitrary code.
The record classifies CVE-2026-45185 under weakness class CWE-416. 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 confidentiality, integrity, availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 169 days ago.
Severity and exploitation probability
- CVSS v3.1 base score
- 9.8 — CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - EPSS (FIRST)
- 0.9% probability of exploitation in the next 30 days, higher than 59.8% of all scored CVEs
- CISA KEV
- Not listed in the CISA Known Exploited Vulnerabilities catalog
- Threadlinqs priority
- 9.3/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- Published
- 2026-05-12, last modified 2026-05-14
Is CVE-2026-45185 being exploited?
Weaponised exploit code for CVE-2026-45185 is publicly available. 5 public proof-of-concept repositories are tracked for this identifier. It currently carries a trending score of 28 in the Threadlinqs vulnerability feed.
- MJ-bin/POC_CVE-2026-45185 (github)
- liamromanis101/Dead.Letter-CVE-2026-45185 (github)
- materaj2/cve-2026-45185-detection-script (github)
- 0init/CVE-2026-45185 (github)
- trickest/cve (trickest)
Affected products and versions
- Exim: Exim
How to fix CVE-2026-45185
No vendor patch reference has been recorded for CVE-2026-45185 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-2026-45185
1 tracked threat in the Threadlinqs corpus references CVE-2026-45185, either in the campaign’s CVE list or as an indicator on the campaign record.
Sources
Enriched from CVE.org, FIRST EPSS, public proof-of-concept repositories. Last verified by Threadlinqs on .
Other references
Showing 5 of 7 recorded references.