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CVE-2026-40687

CRITICALCVSS 9.1/10EPSS 0.37%

Last modified

CVE-2026-40687 is a critical-severity vulnerability rated 9.1/10 on the CVSS scale. 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.. EPSS estimates a 0.37% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
9.1/10

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

EPSS Probability
0.37%

29.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
EximExim< 4.99.2

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is 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-of-bounds write that crashes the connection instance, or erroneous data processing that divulges data from uninitialized heap memory.
How severe is CVE-2026-40687?
CVE-2026-40687 has a CVSS score of 9.1/10 (CRITICAL severity). The EPSS model estimates a 0.37% probability of exploitation in the next 30 days.
How do I fix CVE-2026-40687?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-40687?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST