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CVE-2026-100277

HIGH 8.9

Published 2026-09-30 · Last modified 2026-10-01

In JetBrains YouTrack before 2026.2.19197 account takeover was possible by replaying a notification signature

ELEVATED IMPACT

Severe if exploited (CVSS 8.9), but no known exploitation and low modeled probability. Patch on a normal cadence.

Exploitation likelihood

0.3%chance of exploitation in 30 days · 20th percentile

○ In CISA KEV ○ Public exploit / PoC

Impact if exploited

8.9CVSS 3.1 · HIGH

  • ConfidentialityHigh
  • IntegrityHigh
  • AvailabilityLow

What an attacker needs

  • ✓Access: Reachable over the network — no local access needed
  • ✓Privileges: No account or privileges required
  • ✓User interaction: No user interaction needed
  • ⚠Complexity: Needs a race window or specific setup

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept & exploit code

Test against your own equipment

curl -s https://vulnpedia.com/cve/CVE-2026-100277/poc.jsonMachine-readable PoC index for this CVE (for automation).

Listed for defensive triage, patch verification, and authorized testing on systems you own. Machine-readable: /cve/CVE-2026-100277/poc.json

Affected

Vendors Jetbrains

Products Youtrack

Weakness (CWE)

  • CWE-863: Incorrect authorization

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:L

Known Affected Software Configurations

VendorProductVersion range
JetbrainsYoutrack< 2026.2.19197

All CVSS metrics

  • HIGH 8.9 v3.1 · CNA Primary
    CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:L
  • HIGH 8.9 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:L
  • CRITICAL 9.8 v3.1 · NVD Primary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References

Advisories

Sources: NVD · CVE.org · EPSS