CVE-2026-45185: exim · CVE-2026-45185 is a use-after-free
Affects eximSource CVE Database V5
Not known to be exploited : upgrade to 4.99.3 as a priority.
Data as of 26 Oct 2026, 13:47 UTC
Rated Critical by the CNA (mitre) · No CVSS score from NVD or the CNA
- EPSS
- 1.2% chance of exploitation in 30 days – higher than 69% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 4.99.3
Exploitation evidence
Disclosed: evidence found.
CVE published 12 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade Exim and exim/exim to 4.99.3.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| EximExim | Affected
| Fixed in
|
Eximexim/eximpkg:deb/exim/eximOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
If you cannot patch yet, consider mitigating exposure by restricting access to the mail server or disabling vulnerable configurations if feasible.
Description
CVE-2026-45185 is a use-after-free vulnerability in Exim versions before 4.99.3 when configured with certain GnuTLS settings. It occurs in the BDAT body parsing path during a CHUNKING transfer if a client sends a TLS close_notify mid-body followed by a final cleartext byte on the same TCP connection. This can cause heap corruption and potentially allow an unauthenticated remote attacker to execute arbitrary code.
References
- exim.org (opens in a new tab)
- code.exim.org/exim/wiki/wiki/EximSecurity (opens in a new tab)
- exim.org/static/doc/security/CVE-2026-45185.txt (opens in a new tab)
- xbow.com/blog/dead-letter-cve-2026-45185-xbow-found-rce-exim (opens in a new tab)
- news.ycombinator.com/item?id=48111748 (opens in a new tab)
- openwall.com/lists/oss-security/2026/05/12/4 (opens in a new tab)
- exim.org/static/doc/security/EXIM-Security-2026-05-01.1/ (opens in a new tab)