Medium [CVE-2026-19550] trust-fetch-domains uses trust-read ACI to gate a privileged AD trust refresh, allowing unauthorized LDAP writes
This medium-severity Red Hat Linux advisory covers CVE-2026-19550 affecting Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8.
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Summary
A flaw was found in FreeIPA.
The trust-fetch-domains command is gated by a read-only permission on the trust object rather than a trust-administration permission, allowing an authenticated, non-privileged IPA user to trigger a privileged Active Directory trust refresh using an attacker-supplied server and credentials, resulting in unauthorized, attacker-controlled modification of trusted-domain and ID-range identity data in the IPA LDAP directory.
This flaw only affects Identity Management (IdM/FreeIPA) servers where a cross-forest trust with Active Directory has been established (via ipa-adtrust-install and ipa trust-add). Servers without an active AD trust are not affected, since the trust object and the ADTRUST component required to reach the vulnerable code path do not exist in that configuration.
Exploitation requires network reachability from the IdM server to attacker-controlled infrastructure, but only an ordinary, non-administrative IdM user account — no delegated administrative privilege of any kind is required, and this is not a case of a narrow administrative delegation being used beyond its intended scope.
Red Hat severity: Moderate — CVSS 4.3 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N). Weakness: CWE-863.
Affected Red Hat products: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 7; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
Mitigation checklist
- Administrators of IdM/FreeIPA servers with an Active Directory trust configured can reduce exposure by restricting the default "System: Read Trust Information" permission so it is no longer granted to all authenticated users. This is a suggested compensating control, and should be tested before applying in production, since "System: Read Trust Information" may be relied on by other legitimate read-only lookups (e.g. SSSD subdomain support, per the permission's own code comment).
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
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