Description
Exim through 4.93 has an out-of-bounds read in the SPA authenticator that could result in SPA/NTLM authentication bypass in auths/spa.c and auths/auth-spa.c.
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 | 4.93-16 | — |
| Debian 13 | exim4 | 4.93-16 | — |
| Debian 12 | exim4 | 4.93-16 | — |
| Debian 10 | exim4 | 4.92-8+deb10u4 | DSA-4687-1 |
| Debian 9 | exim4 | 4.89-2+deb9u7 | DSA-4687-1 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 8 | exim4 | 4.84.2-2+deb8u7 | DLA-2213-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | exim4 | 4.93-13ubuntu1.1 | USN-4366-1 |
| Ubuntu 18.04 LTS | exim4 | 4.90.1-1ubuntu1.5 | USN-4366-1 |
| Ubuntu 16.04 LTS | exim4 | 4.86.2-2ubuntu2.6 | USN-4366-1 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 14.04 LTS | exim4 | 4.82-3ubuntu2.4+esm2 | USN-4366-1 |
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 | 4.93-r1 | — |
| Alpine v3.23 | exim | 4.93-r1 | — |
| Alpine v3.22 | exim | 4.93-r1 | — |
| Alpine v3.21 | exim | 4.93-r1 | — |
| Alpine v3.20 | exim | 4.93-r1 | — |
Show 9 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | exim | 4.93-r1 | — |
| Alpine v3.18 | exim | 4.93-r1 | — |
| Alpine v3.17 | exim | 4.93-r1 | — |
| Alpine v3.16 | exim | 4.93-r1 | — |
| Alpine v3.15 | exim | 4.93-r1 | — |
| Alpine v3.14 | exim | 4.93-r1 | — |
| Alpine v3.13 | exim | 4.93-r1 | — |
| Alpine v3.12 | exim | 4.93-r1 | — |
| Alpine v3.11 | exim | 4.93-r1 | — |
Advisories 7
- USN-4366-1 exim4 vulnerability Ubuntu Security Notices (USN) · Jun 29, 2026
- DSA-4687-1 exim4 - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-2213-1 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
- https://bugs.exim.org/show_bug.cgi?id=2571
- https://git.exim.org/exim.git/commit/57aa14b216432be381b6295c312065b2fd034f86
- https://git.exim.org/exim.git/commit/a04174dc2a84ae1008c23b6a7109e7fa3fb7b8b0
- DSA-4687 vendor-advisory
- [debian-lts-announce] 20200518 [SECURITY] [DLA 2213-1] exim4 security update mailing-list
- USN-4366-1 vendor-advisory
- FEDORA-2020-93d7305d71 vendor-advisory
- FEDORA-2020-2e084c987d vendor-advisory
- [oss-security] 20210504 21Nails: Multiple vulnerabilities in Exim mailing-list