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CVE-2026-40687

Published: Apr 30, 2026Updated: May 1, 2026 Sources: CVE List NVDCWE-909

No Known Exploits

Patch Available

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.

CVSS Vector Breakdown

Exploitability

AV:NAttack Vector

Network

AC:HAttack Complexity

High

PR:NPrivileges Required

None

UI:NUser Interaction

None

Scope

S:UScope

Unchanged

Impact

C:LConfidentiality

Low

I:NIntegrity

None

A:LAvailability

Low

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Weaknesses

Affected Products

On-prem

Communications / email-server-client

On-prem

Communications / email-server-client

eximoss-projectCommunications

Exploitability

Official Patch Available

References

https://code.exim.org/exim/exim/commit/68b963b9f75ca27b38e1c0f8c87037990199f505

https://exim.org/static/doc/security/CVE-2026-40687.txt

https://exim.org/static/doc/security/cve-2026-04.1/CVE2026-40687.assessment

and 1 more references View all →

Timeline

Published

Apr 30, 2026

Last Updated

May 1, 2026

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