CVE-2026-27469Public exploitNetwork attack vector

Stored XSS via unescaped comment attributes

Published Feb 21, 2026 · Updated Feb 21, 2026

Stored XSS in Isso before 0.13.2 allows remote attackers to run script in visitors' browsers through crafted website and author fields. Comment write and edit paths either call html.escape with quote=False or omit escaping, while the frontend inserts the website value into a single-quoted href attribute. Anonymous posting is possible when moderation is disabled, and a visitor triggers the stored event handler by loading the comments and moving the pointer.

CVSS severity6.1
Medium
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in Isso before 0.13.2 allows remote attackers to run script in visitors' browsers through crafted website and author fields. Comment write and edit paths either call html.escape with quote=False or omit escaping, while the frontend inserts the website value into a single-quoted href attribute. Anonymous posting is possible when moderation is disabled, and a visitor triggers the stored event handler by loading the comments and moving the pointer.

The record

CVE
CVE-2026-27469
Published
Feb 21, 2026
Updated
Feb 21, 2026
Vendor
Isso
Product
Isso
Classifications
CWE-116, CWE-79, T1189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 21, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 21, 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=< 0afbfe0691ee237963e8fb0b2ee01c9e55ca2144

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Isso · Issoversion=< 0afbfe0691ee237963e8fb0b2ee01c9e55ca2144

Published CVSS scores

6.1GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A: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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-116Improper Encoding or Escaping of Output
CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1189Drive-by Compromise

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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