CVE-2026-33757 | OpenBao up to 2.5.1 JWT/OIDC callback_mode session fixiation

VDB-353927 · CVE-2026-33757 · GCVE-0-2026-33757 OPENBAO UP TO 2.5.1 JWT/OIDC CALLBACK_MODE SESSION FIXIATION HISTORYDIFFRELATEJSONXMLCTI CVSS Meta Temp Score Current Exploit Price (≈) CTI Interest Score 7.8 $0-$5k 1.27+ Summaryinfo A vulnerability was found in OpenBao up to 2.5.1. It has been rated as critical. This affects the function callback_mode of the component JWT/OIDC. The manipulation leads to session fixiation. This vulnerability is uniquely identified as CVE-2026-33757. The attack is possible to be carried out remotely. No exploit exists. Upgrading the affected component is advised. Detailsinfo A vulnerability, which was classified as critical, has been found in OpenBao up to 2.5.1. This issue affects the function callback_mode of the component JWT/OIDC. The manipulation with an unknown input leads to a session fixiation vulnerability. Using CWE to declare the problem leads to CWE-384. Authenticating a user, or otherwise establishing a new user session, without invalidating any existing session identifier gives an attacker the opportunity to steal authenticated sessions. Impacted is confidentiality, integrity, and availability. The summary by CVE is: OpenBao is an open source identity-based secrets management system. Prior to version 2.5.2, OpenBao does not prompt for user confirmation when logging in via JWT/OIDC and a role with `callback_mode` set to `direct`. This allows an attacker to start an authentication request and perform "remote phishing" by having the victim visit the URL and automatically log-in to the session of the attacker. Despite being based on the authorization code flow, the `direct` mode calls back directly to the API and allows an attacker to poll for an OpenBao token until it is issued. Version 2.5.2 includes an additional confirmation screen for `direct` type logins that requires manual user interaction in order to finish the authentication. This issue can be worked around either by removing any roles with `callback_mode=direct` or enforcing confirmation for every session on the token issuer side for the Client ID used by OpenBao. It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-33757 since 03/23/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. It demands that the victim is doing some kind of user interaction. Technical details of the vulnerability are known, but there is no available exploit. Upgrading to version 2.5.2 eliminates this vulnerability. Productinfo Name OpenBao Version 2.5.0 2.5.1 Website Product: https://github.com/openbao/openbao/ CPE 2.3info 🔒 🔒 CPE 2.2info 🔒 🔒 CVSSv4info VulDB Vector: 🔒 VulDB Reliability: 🔍 CVSSv3info VulDB Meta Base Score: 7.9 VulDB Meta Temp Score: 7.8 VulDB Base Score: 6.3 VulDB Temp Score: 6.0 VulDB Vector: 🔒 VulDB Reliability: 🔍 CNA Base Score: 9.6 CNA Vector (GitHub_M): 🔒 CVSSv2info Vector Complexity Authentication Confidentiality Integrity Availability Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock VulDB Base Score: 🔒 VulDB Temp Score: 🔒 VulDB Reliability: 🔍 Exploitinginfo Class: Session fixiation CWE: CWE-384 CAPEC: 🔒 ATT&CK: 🔒 Physical: No Local: No Remote: Yes Availability: 🔒 Status: Not defined Price Prediction: 🔍 Current Price Estimation: 🔒 0-Day Unlock Unlock Unlock Unlock Today Unlock Unlock Unlock Unlock Threat Intelligenceinfo Interest: 🔍 Active Actors: 🔍 Active APT Groups: 🔍 Countermeasuresinfo Recommended: Upgrade Status: 🔍 0-Day Time: 🔒 Upgrade: OpenBao 2.5.2 Timelineinfo 03/23/2026 CVE reserved 03/27/2026 +4 days Advisory disclosed 03/27/2026 +0 days VulDB entry created 03/27/2026 +0 days VulDB entry last update Sourcesinfo Product: github.com Advisory: github.com Status: Confirmed CVE: CVE-2026-33757 (🔒) GCVE (CVE): GCVE-0-2026-33757 GCVE (VulDB): GCVE-100-353927 Entryinfo Created: 03/27/2026 15:48 Changes: 03/27/2026 15:48 (64) Complete: 🔍 Cache ID: 99:7F7:101 Discussion No comments yet. Languages: en. Please log in to comment. ◂ PreviousOverviewNext ▸