CVE-2026-40687
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/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Exim | Exim | < 4.99.2 |
References
- https://www.openwall.com/lists/oss-security/2026/04/30/21Mailing List, Third Party Advisory
Timeline
- Published
- Last Modified
- Status
- Analyzed
Frequently Asked Questions
What is CVE-2026-40687?
How severe is CVE-2026-40687?
How do I fix CVE-2026-40687?
How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
- Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
- PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
- AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.
Related CVEs from 2026
- CVE-2026-4068The Add Custom Fields to Media plugin for WordPress is vulne…4.3
- CVE-2026-40682XML External Entity (XXE) via Unsanitized Dictionary Parsing…9.1
- CVE-2026-40683In OpenStack Keystone before 28.0.1, the LDAP identity backe…7.7
- CVE-2026-40684In Exim before 4.99.2, on systems using musl libc (not glibc…7.5
- CVE-2026-40685In Exim before 4.99.2, when JSON lookup is enabled, an out-o…9.8
- CVE-2026-40686In Exim before 4.99.2, when utf8 operators are enabled, ther…5.3
- CVE-2026-40688An out-of-bounds write vulnerability [CWE-787] vulnerability…7.2
- CVE-2026-4069The Alfie – Feed Plugin plugin for WordPress is vulnerable t…6.1
- CVE-2026-40690The asset dependency graph did not restrict nodes by the vie…4.3
- CVE-2026-40691In Unbound 1.9.0 up to and including 1.25.1, when a DNSCrypt…7.5
- CVE-2026-40698A vulnerability exists in BIG-IP and BIG-IQ systems where a …8.7
- CVE-2026-40699A vulnerability exists in the undisclosed pages in the Confi…7.1
Are you affected by CVE-2026-40687?
Run a free Strix scan to check your systems for this vulnerability.
Scan your code nowSource: NVD / NIST