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TI-2023-22484 Aliases CVE-2023-42116GHSA-5hxx-p89v-jxc7

Stack-based buffer overflow in Exim

Priority MEDIUM 49CWE-121Published · 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
No fix listed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-121 and the CVSS impact.

Summary

Exim SMTP Challenge Stack-based Buffer Overflow Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of Exim. Authentication is not required to exploit this vulnerability. The specific flaw exists within the handling of NTLM challenge requests. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a fixed-length stack-based buffer. An attacker can leverage this vulnerability to execute code in the context of the service account. . Was ZDI-CAN-17515.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.03787 90th percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

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

Affected products

VendorProductAffected versionsFixed inStatusSource
EximEximexim 4.95—No fix listedCNA
  • Exim VendorExim Affected exim 4.95 Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:exim:exim:*:*:*:*:*:*:*:*before 4.96.1VulnerableExim
  • cpe:2.3:a:exim:exim:*:*:*:*:*:*:*:* Versions before 4.96.1 Vulnerable ·Exim

Remediation

No fixed version listed by the sources yet.

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-2023-42116
  2. 2026-10-03 Alias added: GHSA-5hxx-p89v-jxc7
  3. 2026-11-05 EPSS moved to the 90th–95th percentile

References

Advisory 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