CVE-2026-55987
HIGH 8.1 PoC AVAILABLEOAuth2 sign-in reactivates an administrator-deactivated account on auth sources without refresh tokens (incomplete fix of #38009)
EXPLOIT AVAILABLE
Public exploit or PoC code exists. Modeled probability is still low, but the barrier to attack is reduced — watch closely.
Exploitation likelihood
0.3%chance of exploitation in 30 days · 22nd percentile
○ In CISA KEV
● Public exploit / PoC
Impact if exploited
8.1CVSS 3.1 · HIGH
- ConfidentialityHigh
- IntegrityHigh
- AvailabilityNone
What an attacker needs
- ✓Access: Reachable over the network — no local access needed
- ⚠Privileges: Requires a low-privilege account
- ✓User interaction: No user interaction needed
- ✓Complexity: No special conditions — reliably repeatable
✓ lowers the bar for an attacker · ⚠ raises it
Proof of concept & exploit code
- reference https://github.com/go-gitea/gitea/security/advisories/GHSA-vrhc-jjfc-m3m3
- github-search Search GitHub for public PoC repos
Test against your own equipment
curl -s https://vulnpedia.com/cve/CVE-2026-55987/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-2026-55987/poc.json
Weakness (CWE)
- CWE-863: Incorrect authorization
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
All CVSS metrics
- HIGH 8.1 v3.1 · ADP Primary
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N - HIGH 8.1 v3.1 · NVD Secondary
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N