Kyoo is a self-hosted media server focused on movies, series, and anime. Prior to 5.1.0, an unauthenticated attacker could initiate the OIDC login flow with an attacker-controlled redirectUrl. The login handling in auth/oidc.go stored that URL with the opaque login state, and /auth/oidc/logged/{provider} appended the provider, token, and error values before redirecting the victim's browser without validating the destination. Because the one-use token was not bound to the browser session that initiated login, an attacker who induced a victim to complete OIDC authentication could capture the token at the attacker-controlled destination and exchange it through /auth/oidc/callback/{provider} for the victim's Kyoo session. This issue is fixed in version 5.1.0.
CVE-2026-77386
This medium-severity CVE scores 6.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4%, top 67% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
- Lower severity and no public exploit yet
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 6.5
- EG Score
- 6.5(medium)
- EG Risk
- 34(Track)EG Risk 34/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity65% × 45%Exploitation0% × 40%Automatability30% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 0%
- EPSS %ILE
- 33%
- KEV
- Not listed
Published
September 18, 2026
Last Modified
September 18, 2026
Advisory Details (4)
Auto-updated Sep 18, 2026v5.1.0
Patch available: zoriya/Kyoo v5.1.0
https://github.com/zoriya/Kyoo/releases/tag/v5.1.0commit 02ab3af8127a (zoriya/Kyoo)
Patch available: zoriya/Kyoo v5.1.0 (contains commit 02ab3af8127a)
https://github.com/zoriya/Kyoo/commit/02ab3af8127a081295fd7bed103847173c0d7632Whitelist oidc redirect urls
Patch available: zoriya/Kyoo v5.1.0 (PR #1576 merged 2026-07-12)
https://github.com/zoriya/Kyoo/pull/1576OIDC login token can be redirected to an attacker-controlled URL · Advisory · zoriya/Kyoo · GitHub
https://github.com/zoriya/Kyoo/security/advisories/GHSA-xhg6-v78p-xf44Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 5× in last 7d / 5× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-09-20 20:16 UTCEPSS rescore
- 2026-09-19 18:28 UTCEG score recompute
- 2026-09-18 18:27 UTCEG score recompute
- 2026-09-18 17:19 UTCEG score recompute
- 2026-09-18 17:19 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Same CWE
10 shownCWE-601
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Dependency Blast Radius
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