Description
In Exim before 4.99.2, on systems using musl libc (not glibc), an attacker can crash the connection instance when malformed DNS data is present in PTR records. This is caused by a dn_expand oddity in octal printing.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Exim | Exim | < 4.99.2 | 4.99.2 |
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 | 4.99.2-1 | — |
| Debian 13 | exim4 | 4.98.2-1+deb13u2 | — |
| Debian 12 | exim4 | 4.96-15+deb12u9 | — |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | exim | 4.98.2-r0 | — |
| Alpine v3.23 | exim | 4.98.2-r0 | — |
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | exim +9 | 4.99.5-r0 | — |
Advisories 1
- WID-SEC-2026-1334 Exim und cPanel/WHM: Mehrere Schwachstellen BSI CERT-Bund (WID) · Aug 13, 2026