CVE-2026-65986Network attack vectorHinoki check available

Stored XSS via mismatched asset media types

Published Aug 4, 2026 · Updated Aug 4, 2026

Stored XSS in annotation guide assets in CVAT 2.5.0 through 2.66.0 allows remote authenticated users to execute JavaScript in a victim session. Asset uploads accept a user-supplied Content-Type, but retrieval derives the response type from the filename, so disguised HTML is served as executable content. Exploitation requires permission to edit an annotation guide and a victim to open the asset URL, granting access to every CVAT resource available to that victim.

CVSS severity8.5
High
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Stored XSS in annotation guide assets in CVAT 2.5.0 through 2.66.0 allows remote authenticated users to execute JavaScript in a victim session. Asset uploads accept a user-supplied Content-Type, but retrieval derives the response type from the filename, so disguised HTML is served as executable content. Exploitation requires permission to edit an annotation guide and a victim to open the asset URL, granting access to every CVAT resource available to that victim.

The record

CVE
CVE-2026-65986
Published
Aug 4, 2026
Updated
Aug 4, 2026
Vendor
CVAT.ai
Product
CVAT
Classifications
CWE-79, CWE-434, T1203
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 4, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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=>= 2.5.0, < 2.67.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

CVAT.ai · CVATversion=>= 2.5.0, < 2.67.0

Published CVSS scores

8.5GitHubCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA: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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CWE-434Unrestricted Upload of File with Dangerous Type
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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