Authentication Bypass by Alternate Name in sentry - #VU156658
Published: October 21, 2026
Vulnerability identifier: #VU156658
CSH Severity: Medium
CVSS v4: 8.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-289
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to take over a victim's Sentry account.
The vulnerability exists due to improper email matching in Sentry's SAML SSO implementation when processing email claims containing lookalike domain names. A remote user can configure a malicious SAML server to emit an email claim using the dotless-i character ı (U+0131), such as foo@vıctim.com instead of foo@victim.com, to impersonate the victim and take over their account.
For self-hosted instances, exploitation requires SENTRY_SINGLE_ORGANIZATION to be False.
Affected software
sentry
Remediation
Install security update from vendor's website.
sentry - update to 26.10.0