CVE-2026-81807Network attack vector

Stored XSS via unescaped chat message linkification

Published Sep 2, 2026 · Updated Sep 2, 2026

Stored XSS in Jeff Starr Simple Ajax Chat before 20260827 allows remote attackers to execute scripts via crafted chat messages. The chat message linkification path renders stored message content without escaping HTML attributes, so crafted attributes execute in each viewer's browser. Open Air mode permits unauthenticated posting, and any viewer, including an administrator, triggers the payload by loading the chat.

CVSS severityUnavailable
Unscored
EPSS probability0.28%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

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Summary

What happened

Stored XSS in Jeff Starr Simple Ajax Chat before 20260827 allows remote attackers to execute scripts via crafted chat messages. The chat message linkification path renders stored message content without escaping HTML attributes, so crafted attributes execute in each viewer's browser. Open Air mode permits unauthenticated posting, and any viewer, including an administrator, triggers the payload by loading the chat.

The record

CVE
CVE-2026-81807
Published
Sep 2, 2026
Updated
Sep 2, 2026
Vendor
Plugin Planet
Product
Simple Ajax Chat
Classifications
CWE-79, T1189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 2, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 2, 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 <20260827

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Plugin Planet · Simple Ajax Chatversion=0 <20260827

Published CVSS scores

No CVSS assessment is available in this record.

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.

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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 exploitUnconfirmed

Weakness, pattern, technique

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

Public exploit references

No public exploit references are available in this record.

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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