Home/CVE/In Exim before 4.99.2, when the SPA authentication driver is used with an adversarial SPA resource, there can be an out-
CVE

CVE-2026-40687

In Exim before 4.99.2, when the SPA authentication driver is used with an adversarial SPA resource, there can be an out-

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.

MEDIUM · CVSS 4.8 EPSS 0.00182
Monitor
  • No active-exploitation, high-EPSS, or public-exploit signals - routine patching cadence
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-909Missing Initialization of Resource
▤

Affected Products & Versions

1
exim< 4.99.2
▣

Scoring & Timeline

4.8
MEDIUM · CVSS v3.1 · cve@mitre.org
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD30 Apr 2026 · 10:16 PM
CVSS VectorCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L
SSVC triage · cisa-vulnrichment
Exploitation
none
Automatable
no
Technical impact
partial
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
⚑

Vendor Advisories

1
usnUSN-8228-1
🔗

References & Sources

4
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://code.exim.org/exim/exim/commit/68b963b9f75ca27b38e1c0f8c87037990199f505Patch
https://exim.org/static/doc/security/CVE-2026-40687.txtBroken Link
https://exim.org/static/doc/security/cve-2026-04.1/CVE2026-40687.assessmentVendor Advisory
https://www.openwall.com/lists/oss-security/2026/04/30/21Mailing ListThird Party Advisory
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