Ech0 before 4.7.3 OAuth Redirect URI Validation Bypass

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-79662
StatePUBLISHED
AssignerVulnCheck
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-25 12:16:31 UTC
Updated2026-08-25 15:16:45 UTC
DescriptionEch0 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.

Risk And Classification

Primary CVSS: v4.0 8.8 HIGH from [email protected]

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Problem Types: CWE-601 | CWE-601 URL Redirection to Untrusted Site ('Open Redirect')

VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary8.8HIGHCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N/E:X/C...
4.0CNACVSS8.8HIGHCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N
3.1[email protected]Secondary8HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N
3.1CNACVSS8HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
High
Attack Requirements
Present
Privileges Required
None
User Interaction
Passive
Confidentiality
High
Integrity
High
Availability
None
Sub Conf.
High
Sub Integrity
High
Sub Availability
None

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
Required
Scope
Changed
Confidentiality
High
Integrity
High
Availability
None

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Lin-snow Ech0 affected 4.7.3 semver Not specified
CNA Lin-snow Ech0 unaffected 4.7.3 semver Not specified

References

ReferenceSourceLinkTags
www.vulncheck.com/advisories/ech0-before-oauth-redirect-uri-validation-bypass [email protected] www.vulncheck.com
github.com/lin-snow/Ech0/security/advisories/GHSA-p64j-f4x9-wq66 134c704f-9b21-4f2e-91b3-4a467353bcc0 github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: adrgs (en)

CNA: aisafe-bot (en)

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