CVE-2026-79663Public exploitNetwork attack vectorHinoki check available

Subscriber-side script execution via unescaped RSS content

Published Aug 25, 2026 · Updated Aug 26, 2026

Stored XSS in lin-snow Ech0 before 4.7.3 allows remote authenticated users to execute JavaScript in RSS readers through the public feed. GenerateRSS inserts tag.Name through an unescaped string format, while MdToHTML permits raw HTML before both results enter an Atom summary marked as HTML. Echo creation requires an administrator, and execution occurs only when a subscriber's RSS reader decodes and renders HTML summaries, exposing data and actions in that reader's origin.

CVSS severity4.8
Medium
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Stored XSS in lin-snow Ech0 before 4.7.3 allows remote authenticated users to execute JavaScript in RSS readers through the public feed. GenerateRSS inserts tag.Name through an unescaped string format, while MdToHTML permits raw HTML before both results enter an Atom summary marked as HTML. Echo creation requires an administrator, and execution occurs only when a subscriber's RSS reader decodes and renders HTML summaries, exposing data and actions in that reader's origin.

The record

CVE
CVE-2026-79663
Published
Aug 25, 2026
Updated
Aug 26, 2026
Vendor
lin-snow
Product
Ech0
Classifications
CWE-79, CWE-116, T1059.007
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Aug 25, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 26, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <4.7.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

lin-snow · Ech0version=0 <4.7.3

Published CVSS scores

4.8lin-snowCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
4.8VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesadmin
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CWE-116Improper Encoding or Escaping of Output
T1059.007JavaScript/JScript

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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