The vulnerability allows unauthorized disclosure of shared mailbox message history in JetBrains YouTrack before version 2026.2.19562. Attackers can retrieve previously exchanged messages, exposing sensitive data. It is a confidentiality compromise classified under CWE‑863 and carries a CVSS score of 7.7, indicating a moderate‑to‑high threat level.

JetBrains YouTrack versions earlier than 2026.2.19562 are affected. The issue is limited to the shared mailbox feature and applies to all instances configured with this integration.

The CVSS score of 7.7 signifies significant risk. EPSS data is not available, so the current likelihood of exploitation is unknown; however, the issue is not listed in CISA KEV. Based on the description, the likely attack vector involves a user with access to the shared mailbox link, potentially enabling remote or internal exploitation. No complicating prerequisites are stated, so an attacker who can trigger the feature may derive the disclosure.