Exim 4 before 4.94.2 allows Use After Free in smtp_reset in certain situations that may…
Priority HIGH 75CWE-416Published · 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-416 and the CVSS impact.
Summary
Exim 4 before 4.94.2 allows Use After Free in smtp_reset in certain situations that may be common for builds with OpenSSL.
Why it matters now
EPSS 0.56475 99th percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | — | all versions | — | No fix listed | CNA |
- — Vendor— Affected all versions Fixed in — No fix listed CNA
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2020-28018
- 2026-10-03 Alias added: GHSA-5hqr-vx33-mfmh
References
Advisory 8
- https://www.exim.org/static/doc/security/CVE-2020-qualys/CVE-2020-28018-OCORK.txt
- [oss-security] 20210511 [CVE-2020-28018] Use-After-Free on Exim Question
- [oss-security] 20210511 Re: [CVE-2020-28018] Use-After-Free on Exim Question
- [oss-security] 20210511 Re: [CVE-2020-28018] Use-After-Free on Exim Question
- [oss-security] 20210511 Re: [CVE-2020-28018] Use-After-Free on Exim Question
- [oss-security] 20210511 Re: [CVE-2020-28018] Use-After-Free on Exim Question
- [oss-security] 20210512 Re: [CVE-2020-28018] Use-After-Free on Exim Question
- [oss-security] 20210512 Re: [CVE-2020-28018] Use-After-Free on Exim Question
More Exim vulnerabilities
- 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
Sources
- CVE-2020-28018 · CVE Program
- CVE-2020-28018 · NVD
- FIRST EPSS
- GHSA-5hqr-vx33-mfmh · GitHub Advisory Database · CC BY 4.0
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