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VulnerabilityPublished Updated

CVE-2026-45185: exim · CVE-2026-45185 is a use-after-free

Affects eximSource CVE Database V5

0

Not known to be exploited : upgrade to 4.99.3 as a priority.

Data as of 26 Oct 2026, 13:47 UTC

Severity
Critical

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

  1. Disclosed: evidence found.

    CVE published 12 May 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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

ProductAffectedFixed in
EximEximAffected
  • >=4.97 <4.99.3
Fixed in
  • 4.99.3
Eximexim/eximpkg:deb/exim/eximOther threatsAffected
  • <4.99.3
Fixed in
  • 4.99.3

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

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