Description
Stack-based buffer overflow in Exim 3.35, and other versions before 4, when the sender_verify option is true, allows remote attackers to cause a denial of service and possibly execute arbitrary code during sender verification.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.
Exploit-DB 1
- Exim Sender 3.35 - Verification Remote Stack Buffer Overrun EDB-24093 · remote · May 6, 2004 · verified
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 2
- DSA-502 exim-tls - buffer overflow Debian Security (DSA / DLA) · Mar 9, 2026
- DSA-501 exim - buffer overflow Debian Security (DSA / DLA) · Mar 9, 2026
References
- DSA-502 vendor-advisory
- DSA-501 vendor-advisory
- 20040506 Buffer overflows in exim, yet still exim much better than windows mailing-list
- 11558 third-party-advisory
- exim-requireverify-bo(16079) vdb-entry
- http://www.guninski.com/exim1.html