Description
The receive_msg function in receive.c in the SMTP daemon in Exim 4.88 and 4.89 allows remote attackers to execute arbitrary code or cause a denial of service (use-after-free) via vectors involving BDAT commands.
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 ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | exim4 | 4.89-12 | — |
| Debian 13 | exim4 | 4.89-12 | — |
| Debian 12 | exim4 | 4.89-12 | — |
| Debian 9 | exim4 | 4.89-2+deb9u2 | DSA-4053-1 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SUSE Package Hub 15 SP2 | exim | 4.94.2-bp152.6.4.1 | openSUSE-SU-2021:0754-1 |
| SUSE Package Hub 15 SP2 | libspf2 | 1.2.10-bp152.5.1 | openSUSE-SU-2021:0754-1 |
| SUSE Package Hub 15 SP1 | exim | 4.94.2-bp151.2.4.1 | openSUSE-SU-2021:0753-1 |
| SUSE Package Hub 15 SP1 | libspf2 | 1.2.10-bp151.4.1 | openSUSE-SU-2021:0753-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | exim | 4.94.2-4.2 | openSUSE-SU-2024:10746-1 |
| openSUSE Leap 15.2 | exim | 4.94.2-lp152.8.3.1 | openSUSE-SU-2021:0677-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | exim | 4.89-r7 | — |
| Alpine v3.23 | exim | 4.89-r7 | — |
| Alpine v3.22 | exim | 4.89-r7 | — |
| Alpine v3.21 | exim | 4.89-r7 | — |
| Alpine v3.20 | exim | 4.89-r7 | — |
Show 13 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | exim | 4.89-r7 | — |
| Alpine v3.18 | exim | 4.89-r7 | — |
| Alpine v3.17 | exim | 4.89-r7 | — |
| Alpine v3.16 | exim | 4.89-r7 | — |
| Alpine v3.15 | exim | 4.89-r7 | — |
| Alpine v3.14 | exim | 4.89-r7 | — |
| Alpine v3.13 | exim | 4.89-r7 | — |
| Alpine v3.12 | exim | 4.89-r7 | — |
| Alpine v3.11 | exim | 4.89-r7 | — |
| Alpine v3.10 | exim | 4.89-r7 | — |
| Alpine v3.9 | exim | 4.89-r7 | — |
| Alpine v3.8 | exim | 4.89-r7 | — |
| Alpine v3.7 | exim | 4.89-r7 | — |
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.
GitHub 1 repository
-
beraphin/CVE-2017-16943 ★ 0 · Nov 20, 2018
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 5
- DSA-4053-1 exim4 - security update Debian Security (DSA / DLA) · Mar 9, 2026
- openSUSE-SU-2021:0754-1 Security update for exim SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:10746-1 exim-4.94.2-4.2 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2021:0677-1 Security update for exim SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2021:0753-1 Security update for exim SUSE / openSUSE Security Updates · Feb 4, 2026
References
- 1039872 vdb-entry
- https://lists.exim.org/lurker/message/20171125.034842.d1d75cac.en.html
- https://git.exim.org/exim.git/commit/4090d62a4b25782129cc1643596dc2f6e8f63bde
- http://openwall.com/lists/oss-security/2017/11/25/3
- https://github.com/LetUsFsck/PoC-Exploit-Mirror/tree/master/CVE-2017-16944
- http://openwall.com/lists/oss-security/2017/11/25/1
- https://git.exim.org/exim.git/commitdiff/4e6ae6235c68de243b1c2419027472d7659aa2b4
- http://openwall.com/lists/oss-security/2017/11/25/2
- DSA-4053 vendor-advisory
- https://bugs.exim.org/show_bug.cgi?id=2199
- [oss-security] 20210504 21Nails: Multiple vulnerabilities in Exim mailing-list