CVE-2026-8042Network attack vector

Stored XSS via unescaped repo shortcode attribute

Published May 27, 2026 · Updated May 27, 2026

Stored XSS in octalmage GitHub Shortcode 0.1 and earlier allows remote authenticated users to inject scripts through the repo attribute. The github shortcode callback inserts the attacker-controlled repo value into generated page markup without sanitizing the input or escaping the output. Contributor-level access is required to save the payload; the script runs in visitors' browsers whenever they open the affected page.

CVSS severity6.4
Medium
EPSS probability0.19%
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 octalmage GitHub Shortcode 0.1 and earlier allows remote authenticated users to inject scripts through the repo attribute. The github shortcode callback inserts the attacker-controlled repo value into generated page markup without sanitizing the input or escaping the output. Contributor-level access is required to save the payload; the script runs in visitors' browsers whenever they open the affected page.

The record

CVE
CVE-2026-8042
Published
May 27, 2026
Updated
May 27, 2026
Vendor
octalmage
Product
GitHub Shortcode
Classifications
CWE-79, T1203
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 27, 2026CVE publishedPublication date reported by the CVE source.
  2. May 27, 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 <=0.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

octalmage · GitHub Shortcodeversion=0 <=0.1

Published CVSS scores

6.4WordfenceCVSS:3.1/AV:N/AC:L/PR:L/UI:N/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.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

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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