CVE-2026-40687
9.1
CRITICAL
CVSS 3.1
EPSS 0.18%
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.
How to fix CVE-2026-40687
No fixed version has been published yet. Mitigate by removing the affected package or applying upstream guidance from the references below.
- Debian/exim4—no fix listed
Is CVE-2026-40687 being exploited?
Low — EPSS is 0.2%, meaning exploitation activity has not been observed at scale.
Affected packages (1)
- from 0
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | CRITICAL9.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H |