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Fencer Vulns
medium 5.4

CVE-2024-39929 json

Exim through 4.97.1 misparses a multiline RFC 2231 header filename, and thus remote attackers can bypass a $mime_filename extension-blockin…

published 2024-07-04 2 y ago modified 2026-06-17 4 mo ago also EUVD-2024-38307

cvss
5.4
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
41.5%
EPSS 41.5% chance of exploitation in 30 days, percentile 98%
public exploits
0
none known

Summary

Exim through 4.97.1 misparses a multiline RFC 2231 header filename, and thus remote attackers can bypass a $mime_filename extension-blocking protection mechanism, and potentially deliver executable attachments to the mailboxes of end users.

Patch / fix

  • exim4 Debian 12 4.96-15+deb12u5
  • exim4 Debian 14, Debian 13 4.98~RC3-2

debian advisories DEBIAN-CVE-2024-39929

  • exim4 Ubuntu 20.04 LTS 4.93-13ubuntu1.12
  • exim4 Ubuntu 22.04 LTS 4.95-4ubuntu2.6
  • exim4 Ubuntu 24.04 LTS 4.97-4ubuntu4.1
  • exim4 Ubuntu Pro 16.04 LTS 4.86.2-2ubuntu2.6+esm8
  • exim4 Ubuntu Pro 18.04 LTS 4.90.1-1ubuntu1.10+esm5

ubuntu advisories UBUNTU-CVE-2024-39929

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • exim Package Hub 15 SP5, openSUSE Leap 15.5 4.97.1-bp155.5.12.1
  • exim openSUSE Tumbleweed 4.98-1.1

opensuse advisories openSUSE-SU-2024:0218-1openSUSE-SU-2024:14196-1

  • exim Alpine 3.24, Alpine 3.23, Alpine 3.22 +2 more 4.98-r0

alpine advisories ALPINE-CVE-2024-39929

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2024-39929 updated cvss 3.7

exim: exim: Incorrect parsing of multiline rfc2231 header filename

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

41.49% chance of exploitation in the next 30 days, higher than 98% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • bugs.exim.org https://bugs.exim.org/show_bug.cgi?id=3099#c4 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CISA ADP 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
CNA 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N

Affected products

  • exim exim

Classification

Weakness
  • CWE-116 Improper Encoding or Escaping of Output

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.