CVE-2026-100277 — Youtrack
HIGHCVE-2026-100277 is a high-severity (CVSS 8.9) CWE-863 vulnerability in jetbrains youtrack. A fix is available — see the affected versions and patch details below.
In JetBrains YouTrack before 2026.2.19197 account takeover was possible by replaying a notification signature
Exploitation Status
No confirmed exploitation observed yet
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-100277.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2026-100277 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 385,738 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Description
In JetBrains YouTrack before 2026.2.19197 account takeover was possible by replaying a notification signature
Affected Products
youtrackjetbrainsDetection & mitigation playbook
Vendor / applianceDetect
Inventory every jetbrains youtrack deployment and check each version against the affected-products list above.
Fix
Apply the jetbrains youtrack security patch or hotfix for CVE-2026-100277 on the affected version, following the vendor advisory for your exact build.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used. Alongside that, restrict the management interface to trusted networks and apply the vendor's recommended configuration mitigations.
Frequently Asked Questions
Is CVE-2026-100277 being exploited in your environment?
Detect and block the exploit chain at execution, on systems you cannot patch yet.