| Name | CVE-2026-42395 |
| Description | A host listed as a trusted proxy can send forwarding information containing a NUL byte, which crashes the login process on the following login attempt. The login process is terminated, which can cause degradation or denial of service for logins. Deployments that do not configure trusted proxies are not affected. Restrict the list of trusted proxy networks to hosts that are fully under your control. Update to non-vulnerable version. No publicly available exploits are known. |
| 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) |
| References | DLA-4873-1, DSA-6526-1 |
| Debian Bugs | 1146018 |
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|---|---|---|
| dovecot (PTS) | bookworm | 1:2.3.19.1+dfsg1-2.1+deb12u6 | vulnerable |
| bookworm (security) | 1:2.3.19.1+dfsg1-2.1+deb12u7 | fixed | |
| trixie | 1:2.4.1+dfsg1-6+deb13u6 | vulnerable | |
| trixie (security) | 1:2.4.1+dfsg1-6+deb13u7 | fixed | |
| forky, sid | 1:2.4.5+dfsg1-4 | fixed |
The information below is based on the following data on fixed versions.
| Package | Type | Release | Fixed Version | Urgency | Origin | Debian Bugs |
|---|---|---|---|---|---|---|
| dovecot | source | bookworm | 1:2.3.19.1+dfsg1-2.1+deb12u7 | DLA-4873-1 | ||
| dovecot | source | trixie | 1:2.4.1+dfsg1-6+deb13u7 | DSA-6526-1 | ||
| dovecot | source | (unstable) | 1:2.4.5+dfsg1-1 | 1146018 |
https://documentation.open-xchange.com/dovecot/security/advisories/html/2026/oxdc-adv-2026-0003.html#cve-2026-42395-single-nul-byte-xclient-forward-payload-crashes
Fixed by: https://github.com/dovecot/core/commit/0a1adbe37e03e859681bab6186494600b1c708ac
Fixed by: https://github.com/dovecot/core/commit/991780f2a9d567f9c2f4b136d96b0b35e1d8e9e1