CVE-2026-40687

Out‑of‑Bounds Write and Data Disclosure via Exim SPA Authentication Driver

Published Apr 30, 2026 CVSS 3.1 · 4.8 Medium EPSS < 1% KEV · Not listed
Description
In Exim before 4.99.2, when the SPA authentication driver is used with an adversarial SPA resource, there can be an out-of-bounds write that crashes the connection instance, or erroneous data processing that divulges data from uninitialized heap memory.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Debian DSA Debian DSA DSA-6265-1 exim4 security update
Ubuntu USN Ubuntu USN USN-8228-1 Exim vulnerabilities
Ubuntu USN Ubuntu USN USN-8382-1 Exim vulnerabilities
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Title Out‑of‑Bounds Write and Data Disclosure via Exim SPA Authentication Driver
Type Values Removed Values Added
Description In Exim before 4.99.2, when the SPA authentication driver is used with an adversarial SPA resource, there can be an out-of-bounds write that crashes the connection instance, or erroneous data processing that divulges data from uninitialized heap memory.
First Time appeared Exim
Exim exim
Weaknesses CWE-909
CPEs cpe:2.3:a:exim:exim:*:*:*:*:*:*:*:*
Vendors & Products Exim
Exim exim
References
Metrics cvssV3_1

{'score': 4.8, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
mitre
Published
Updated
May 1, 2026, 2:25 PM
Reserved
Apr 14, 2026, 12:00 AM
Status
Analyzed
Published
Apr 30, 2026, 10:16 PM
Modified
Nov 11, 2026, 9:10 PM