exim4: In Exim before 4.99.2, on systems using musl libc (not glibc), an attacker can crash the connection instance when mal...
CVE-2026-40684 is fixed in exim4 on 1 platform, first by DEBIAN-CVE-2026-40684, released May 15, 2026. It is not reported as exploited. Patch Radar priority: High.
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.
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Linux | |||
| exim4 · Debian 12.15 (bookworm) | 4.96-15+deb12u9 | DEBIAN-CVE-2026-40684 | May 15, 2026 |
| exim4 · Debian 13.5 (trixie) | 4.98.2-1+deb13u2 | DEBIAN-CVE-2026-40684 | May 15, 2026 |
| exim4 · Debian 14 | 4.99.2-1 | DEBIAN-CVE-2026-40684 | May 15, 2026 |
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