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CVE-2026-40686

LOW

3.7

Description

In Exim before 4.99.2, when utf8 operators are enabled, there is an out-of-bounds read if large UTF-8 trailing characters are present (malformed UTF-8 header data). Information might be divulged within an error message produced during handling of an unrelated e-mail message.

CVE Details

CVSS v3.1 Score3.7

SeverityLOW

CVSS VectorCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

Attack VectorNETWORK

ComplexityHIGH

Privileges RequiredNONE

User InteractionNONE

Published4/30/2026

Last Modified5/1/2026

Sourcenvd

Honeypot Sightings0

Affected Products

exim:exim

Weaknesses (CWE)

CWE-125

References

https://code.exim.org/exim/exim/commit/f2570bde16fb4d4a1242ff363a4c4eecf6372efc(cve@mitre.org)

https://exim.org/static/doc/security/CVE-2026-40686.txt(cve@mitre.org)

https://exim.org/static/doc/security/cve-2026-04.1/CVE2026-40686.assessment(cve@mitre.org)

https://www.openwall.com/lists/oss-security/2026/04/30/21(cve@mitre.org)

IOC Correlations

No correlations recorded

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