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TI-2026-29370 Aliases CVE-2026-40685GHSA-pph6-fvmv-fjrc

Out-of-bounds write in Exim

Priority MEDIUM 42CWE-684Published · Updated

Key facts

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

Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-787 and the CVSS impact.

Summary

In Exim before 4.99.2, when JSON lookup is enabled, an out-of-bounds heap write can occur when a JSON operator encounters malformed JSON in an untrusted header, because of an incorrect implementation of \ skipping.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00321 25th 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

    • TI-2026-29372 Missing initialization of resource in EximPriority LOW 39
    • TI-2026-29369 In Exim before 4.99.2, on systems using musl libc (not glibc), an attacker can crash the…Priority LOW 33
    • TI-2026-29371 Out-of-bounds read in EximPriority LOW 24
    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-2026-40685
  2. 2026-10-03 Alias added: GHSA-pph6-fvmv-fjrc

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