Ech0 before 4.7.3 Stored XSS via RSS feed tag names

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-79663
StatePUBLISHED
AssignerVulnCheck
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-25 12:16:33 UTC
Updated2026-08-25 12:16:33 UTC
DescriptionEch0 before 4.7.3 contains a stored cross-site scripting vulnerability in the public RSS feed where tag names and markdown content are rendered without HTML escaping. Attackers with admin privileges can inject malicious tag names or raw HTML in echo content that executes as JavaScript in RSS readers that render HTML-type summaries, affecting anonymous subscribers and other users.

Risk And Classification

Primary CVSS: v4.0 4.8 MEDIUM from [email protected]

CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/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-79 | CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary4.8MEDIUMCVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N/E:X/C...
4.0CNACVSS4.8MEDIUMCVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N
3.1[email protected]Primary4.8MEDIUMCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
3.1CNACVSS4.8MEDIUMCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N

CVSS v4.0 Breakdown

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

CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/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
Low
Privileges Required
High
User Interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/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
github.com/lin-snow/Ech0/security/advisories/GHSA-3v85-fqvh-7rxf [email protected] github.com
www.vulncheck.com/advisories/ech0-before-stored-xss-via-rss-feed-tag-names [email protected] www.vulncheck.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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