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TI-2026-29369 Aliases CVE-2026-40684GHSA-q496-q274-jgh9

In Exim before 4.99.2, on systems using musl libc (not glibc), an attacker can crash the…

Priority LOW 33CWE-684Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00362 30th percentileScored 2026-11-07
Fix Fixed Exim (Exim): 4.99.2

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
EximEximbefore 4.99.24.99.2Patch availableCNA
  • Exim VendorExim Affected before 4.99.2 Fixed in 4.99.2 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:exim:exim:*:*:*:*:*:*:*:*before 4.99.2VulnerableExim
  • cpe:2.3:a:exim:exim:*:*:*:*:*:*:*:* Versions before 4.99.2 Vulnerable ·Exim

Remediation

  • Fix · CNA Exim (Exim) Fixed in 4.99.2

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    Exim 4.99.2

    4 records Highest priority Priority MEDIUM 1 MEDIUM, 3 LOW

    Other records, highest priority first

    Show all 4 records →

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-40684
  2. 2026-10-03 Alias added: GHSA-q496-q274-jgh9

References

Patch 1

Advisory 2

Other 1

  • TI-2019-12627 Exim 4.92 through 4.92.2 allows remote code execution, a different vulnerability than… KEVCVSS 3.1CRITICAL 9.8
  • TI-2019-07471 OS command injection in exim KEVCVSS 3.1CRITICAL 9.8
  • TI-2018-04965 An issue was discovered in the base64d function in the SMTP listener in Exim before… KEVCVSS 3.1CRITICAL 9.8
  • TI-2010-04077 Heap-based buffer overflow in the string_vformat function in string.c in Exim before 4.70… KEVCVSS 3.1CRITICAL 9.8
  • TI-2010-04078 Exim 4.72 and earlier allows local users to gain privileges by leveraging the ability of… KEVCVSS 3.1HIGH 7.8
  • TI-2025-19707 SQL injection in Exim CVSS 3.1CRITICAL 9.8
See all 69 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences