7.5

CVE-2026-40684: exim

CVSS: 7.5v3.1HighModified
AliasesDEBIAN-CVE-2026-40684CGA-288r-jjcq-jhcxCGA-4m3c-7m39-jm53
Published 30-04-2026Last modified 01-05-2026
Open JSON

Vulnerability summary

CVE-2026-40684 is a high (CVSS 7.5) vulnerability in exim. EPSS estimates a 0.61% chance of exploitation in the next 30 days, higher than 48% of scored vulnerabilities.

Overall risk
30/100
0100
Medium · default modelHow is this calculated?
CVSS score
7.5/10
010
High · v3.1 (NVD)
EPSS score
0.61%
0%100%
Low · +0.24 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 0 · Related 1
CGA-HQVH-6F7P-Q95X

Timeline

  1. 30-04-2026
    PublishedVulnerability first disclosed.
  2. 01-05-2026
    Last modifiedVulnerability information updated.

Description

In Exim before 4.99.2, on systems using musl libc (not glibc), an attacker can crash the connection instance when malformed DNS data is present in PTR records. This is caused by a dn_expand oddity in octal printing.

CVSS metrics

3 scores · 3 sources · 1 version

EPSS trend

Probability

0.61%

Chance of exploitation in the next 30 days

Percentile

48%

Versus all other CVEs

30-day change

+0.24 pp

From 0.36% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.61%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Chainguard10 products
  • exim< 4.99.5-r0
  • exim-cdb< 4.99.5-r0
  • exim-dbmdb< 4.99.5-r0
  • exim-dnsdb< 4.99.5-r0
  • exim-doc< 4.99.5-r0
Wolfi10 products
  • exim< 4.99.5-r0
  • exim-cdb< 4.99.5-r0
  • exim-dbmdb< 4.99.5-r0
  • exim-dnsdb< 4.99.5-r0
  • exim-doc< 4.99.5-r0
Debian1 product
  • exim4< 4.96-15+deb12u9 | < 4.98.2-1+deb13u2 | < 4.99.2-1
Exim1 product

4 vendors · 22 products

References

6 links