| Name | CVE-2026-40686 |
| Description | In Exim before 4.99.2, when utf8 operators are enabled, there is an out-of-bounds read if large UTF-8 trailing characters are present (malformed UTF-8 header data). Information might be divulged within an error message produced during handling of an unrelated e-mail message. |
| Source | CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) |
Vulnerable and fixed packages
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|
| exim4 (PTS) | bullseye | 4.94.2-7+deb11u3 | vulnerable |
| bullseye (security) | 4.94.2-7+deb11u4 | vulnerable |
| bookworm, bookworm (security) | 4.96-15+deb12u7 | vulnerable |
| trixie | 4.98.2-1 | vulnerable |
| forky, sid | 4.99.2-1 | fixed |
The information below is based on the following data on fixed versions.
| Package | Type | Release | Fixed Version | Urgency | Origin | Debian Bugs |
|---|
| exim4 | source | (unstable) | 4.99.2-1 | | | |
Notes
[trixie] - exim4 <no-dsa> (Minor issue)
[bookworm] - exim4 <no-dsa> (Minor issue)
[bullseye] - exim4 <postponed> (Minor issue; can be fixed in next update)
Fixed by: https://code.exim.org/exim/exim/commit/f2570bde16fb4d4a1242ff363a4c4eecf6372efc