CVE-2026-42395

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{"bugzilla": {"description": "dovecot: Dovecot: Denial of Service via NUL byte in forwarding information", "id": "2525563", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2525563"}, "csaw": false, "cvss3": {"cvss3_base_score": "6.5", "cvss3_scoring_vector": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-170", "details": ["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.", "A flaw was found in Dovecot. A remote attacker, if able to send forwarding information from a host configured as a trusted proxy, could send a NUL byte that crashes the login process. This termination of the login process can lead to a denial of service for user logins."], "mitigation": {"lang": "en:us", "value": "To mitigate this issue, restrict the `login_trusted_networks` configuration in Dovecot to only include hosts that are fully under administrative control. This prevents unauthorized hosts from sending malformed forwarding information. After modifying the configuration, the Dovecot service must be reloaded or restarted for the changes to take effect."}, "name": "CVE-2026-42395", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "package_name": "dovecot", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Out of support scope", "package_name": "dovecot", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Fix deferred", "package_name": "dovecot", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "dovecot", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "dovecot", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2026-08-28T10:12:29Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-42395\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-42395\nhttps://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0003.json"], "threat_severity": "Moderate"}

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