CVE-2026-84321 is a medium-severity (CVSS 5.4) CWE-613 vulnerability in github.com/0xJacky/Nginx-UI. A fix is available for github.com/0xJacky/Nginx-UI — see the affected versions and patch details below.
Nginx UI: Standalone short tokens survive administrative revocation in cache and authenticate again after account re-enable
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-84321.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2026-84321 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 394,415 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
github.com/0xJacky/Nginx-UIReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Summary
Standalone short tokens issued for WebSocket and explicit-token authentication can survive administrative revocation in cache. If the same account is later re-enabled before the cache entry expires, the deleted short token becomes valid again.
Details
GenerateShortToken() creates an AuthToken row that contains only ShortToken and no long Token. DeleteUserTokens() removes database rows, but when clearing caches it only invalidates entries where authToken.Token != "". This leaves standalone short-token cache entries behind. GetTokenUserByShortToken() checks that cache first and then loads the user by ID, so the stale short token becomes usable again if the account status is restored to true.
Relevant code paths:
- internal/user/user.go
- internal/user/user.go
- internal/user/user.go
- api/user/short_token.go
- internal/middleware/middleware.go
PoC
This was verfied locally in an isolated environment with a temporary package-level harness that exercised the real token issuance, revocation, cache, and re-authentication paths.
What the executed test did:
- Created an enabled user in a temporary SQLite database.
- Called the real
GenerateShortToken(user.ID)function to issue a standalone short token. - Verified that the token authenticated successfully and was present in the short-token cache.
- Disabled the user and called the real
DeleteUserTokens(user.ID)function. - Verified that the database token rows were removed.
- Verified that the short-token cache entry still existed after
DeleteUserTokens. - Re-enabled the same user.
- Reused the previously deleted short token via the real
GetTokenUserByShortToken()path and observed successful authentication.
Observed result from the actual local verification:
- The database token rows were removed during revocation.
- The short-token cache entry remained present.
- Re-enabling the user restored successful authentication through the stale short token.
Impact
Any deployment using standalone short tokens is affected. If a short token is stolen, administrative disable/delete-token handling may not fully revoke it. Re-enabling the account within the cache lifetime restores access for the stale token to any HTTP or WebSocket routes that accept short-token authentication.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/0xJacky/Nginx-UI | all versions | 1.9.10-0.20260703131214-23d1934099b0go get github.com/0xJacky/Nginx-UI@v1.9.10-0.20260703131214-23d1934099b0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/0xJacky/Nginx-UI, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/0xJacky/Nginx-UI to 1.9.10-0.20260703131214-23d1934099b0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-84321 is resolved across your whole dependency graph.
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.
Frequently Asked Questions
Is CVE-2026-84321 in your dependencies?
Find it across Go, including transitive dependencies.