CVE-2026-63135Public exploitNetwork attack vector

Stored XSS via unescaped referrer chart labels

Published Aug 21, 2026 · Updated Aug 21, 2026

Stored XSS in YOURLS 1.5.1 through 1.10.3 allows remote attackers to run JavaScript in a stats viewer's browser via a crafted Referer header. The referrer chart path stores the header, derives its domain, and concatenates that label into inline JavaScript without escaping string metacharacters. Exploitation requires a valid short URL and a later statistics-page view; the script runs in the YOURLS origin and can read admin-visible data or perform privileged same-origin actions.

CVSS severity8.2
High
EPSS probability0.31%
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 YOURLS 1.5.1 through 1.10.3 allows remote attackers to run JavaScript in a stats viewer's browser via a crafted Referer header. The referrer chart path stores the header, derives its domain, and concatenates that label into inline JavaScript without escaping string metacharacters. Exploitation requires a valid short URL and a later statistics-page view; the script runs in the YOURLS origin and can read admin-visible data or perform privileged same-origin actions.

The record

CVE
CVE-2026-63135
Published
Aug 21, 2026
Updated
Aug 21, 2026
Vendor
YOURLS
Product
YOURLS
Classifications
CWE-79, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 21, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 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=>= 1.5.1, < 1.10.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

YOURLS · YOURLSversion=>= 1.5.1, < 1.10.4

Published CVSS scores

8.2GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/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-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

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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