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🛡️ CLSA-2026-1778003565 — exim4 (CVE-2026-40684 +2 more)

⚪ Unknown ✅ No Known Exploit OSV
N/A
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

Fix CVE(s): CVE-2026-40684, CVE-2026-40685, CVE-2026-40687

  • SECURITY UPDATE: out-of-bounds read in DNS reverse-lookup escape

decoding when running against musl libc

  • debian/patches/CVE-2026-40684.patch: harden string_copy_dnsdomain()

to consume 1, 2, or 3 digits incrementally instead of indexing past

the input string when fewer than 3 digits follow a backslash escape

  • CVE-2026-40684
  • SECURITY UPDATE: out-of-bounds heap write in JSON dewrap on malformed

header value ending in a trailing backslash

  • debian/patches/CVE-2026-40685.patch: only skip a backslash in

dewrap() when followed by a non-NUL character

  • CVE-2026-40685
  • SECURITY UPDATE: SPA authenticator out-of-bounds write and

uninitialised-heap information disclosure

  • debian/patches/CVE-2026-40687.patch: zero the spa_base64_to_bits()

output buffer to plug the infoleak; replace assert()-based length

guards in unicodeToString(), strToUnicode(), and toString() with

explicit length clamping to prevent OOB writes

  • CVE-2026-40687

Affected software

CLSA-2026-1778003565 is recorded against 7 packages.

  • exim4 (fixed in 4.93-13ubuntu1.12+tuxcare.els1)
  • exim4-base (fixed in 4.93-13ubuntu1.12+tuxcare.els1)
  • exim4-config (fixed in 4.93-13ubuntu1.12+tuxcare.els1)
  • exim4-daemon-heavy (fixed in 4.93-13ubuntu1.12+tuxcare.els1)
  • exim4-daemon-light (fixed in 4.93-13ubuntu1.12+tuxcare.els1)
  • exim4-dev (fixed in 4.93-13ubuntu1.12+tuxcare.els1)
  • eximon4 (fixed in 4.93-13ubuntu1.12+tuxcare.els1)

Timeline and source

Published on 5 May 2026 and last revised on 4 June 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

errata.tuxcare.com (Advisory)

Other advisories for this package

exim4 has other advisories on record. If you are patching this one, these are worth checking on the same host:

Details

Severity Unknown
CVSS Score N/A
CVSS Vector N/A
CWE N/A
Public Exploit ✅ No
Source OSV
Published 2026-05-05
Updated 2026-08-20
Modified 2026-06-04
Fix URL N/A

Affected Packages

Software From version Fixed in
exim4 — 4.93-13ubuntu1.12+tuxcare.els1
exim4-base — 4.93-13ubuntu1.12+tuxcare.els1
exim4-config — 4.93-13ubuntu1.12+tuxcare.els1
exim4-daemon-heavy — 4.93-13ubuntu1.12+tuxcare.els1
exim4-daemon-light — 4.93-13ubuntu1.12+tuxcare.els1
exim4-dev — 4.93-13ubuntu1.12+tuxcare.els1
eximon4 — 4.93-13ubuntu1.12+tuxcare.els1

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