CVE-2026-79662: high-severity vulnerability in lin-snow Ech0
Ech0 before 4.7.3 OAuth Redirect URI Validation Bypass
Published
21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 8.8epss 0.3%
exploitation probability
0.3%top 75% of all CVEs
observed exploitation
nono source reports it
Ech0 through 4.5.6 contains an OAuth redirect URI validation vulnerability in parseAndValidateClientRedirect (internal/service/auth/auth.go) that compares only the scheme and host of the client-supplied redirect_uri against the admin-configured allowlist, ignoring path, query, and fragment components. The redirect_uri is embedded into the signed state JWT at login time without validation. An attacker can craft a redirect_uri whose host matches an allowed origin but whose path is attacker-influenced; after the OAuth exchange the victim is redirected to that path with a one-time exchange code in the query string. If the code leaks (e.g., via Referer, analytics, or an open redirect on that host), the attacker can trade it at the public POST /api/auth/exchange endpoint for the victim's access and refresh tokens. Fixed in 4.7.3.
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N
Affected products
lin-snow · Ech0Related CVEs — lin-snow Ech0
In the same product, most dangerous first.
CVE-2026-35037HIGHEch0 affected by unauthenticated SSRF in GetWebsiteTitle allows access to internal services and cloud metadataEPSS 0.6%CVE-2026-79665HIGHEch0 before 4.5.1 Authorization Bypass via Session TokensEPSS 0.5%CVE-2026-79658HIGHEch0 before 5.0.1 Denial of Service via Accept-LanguageEPSS 0.5%CVE-2026-33638MEDIUMEch0 authenticated user-list exposed data via public `/api/allusers` endpointEPSS 0.5%CVE-2026-79668MEDIUMEch0 before 4.7.3 Unauthenticated Like Endpoint Metric InflationEPSS 0.4%CVE-2026-79661MEDIUMEch0 before 4.7.3 Unauthenticated fav_count ModificationEPSS 0.4%