CVE-2026-52816Public exploitNetwork attack vector

Cross-site scripting via unrestricted data URI sanitization

Published Jun 24, 2026 · Updated Jun 24, 2026

Cross-site scripting in Gogs before 0.14.3 allows remote attackers to execute JavaScript through a crafted Jupyter Notebook sanitizer request. The POST /-/api/sanitize_ipynb endpoint applies bluemonday.UGCPolicy with unrestricted data URI approval, preserving data:text/html payloads in returned HTML. Network access to the unauthenticated endpoint is sufficient; code runs only when the returned content is rendered in a browser, where it can read or alter data available to that browser session.

CVSS severityUnavailable
Unscored
EPSS probability0.68%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in Gogs before 0.14.3 allows remote attackers to execute JavaScript through a crafted Jupyter Notebook sanitizer request. The POST /-/api/sanitize_ipynb endpoint applies bluemonday.UGCPolicy with unrestricted data URI approval, preserving data:text/html payloads in returned HTML. Network access to the unauthenticated endpoint is sufficient; code runs only when the returned content is rendered in a browser, where it can read or alter data available to that browser session.

The record

CVE
CVE-2026-52816
Published
Jun 24, 2026
Updated
Jun 24, 2026
Vendor
Gogs
Product
Gogs
Classifications
CWE-80, T1189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 24, 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=< 0.14.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Gogs · Gogsversion=< 0.14.3

Published CVSS scores

5.4GitHub, Inc.CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N/E:P

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-80Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)
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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