CVE-2026-23516VulnerabilityPublished 21 Jan 2026Updated 26 Feb 2026

CVE-2026-23516: cvat · Improper Neutralization of Script in Attributes in a Web Page

Affects cvatSource CVE Database V5

Not known to be exploited · CVSS 8.6 High : upgrade to 2.55.0 soon.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 4.0 base score

8.6High

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 2.55.0

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: None
User Interaction: Passive
Vulnerable system confidentiality: High
Vulnerable system integrity: High
Vulnerable system availability: None
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction: Passive: Successful exploitation of this vulnerability requires limited interaction by the targeted user with the vulnerable system and the attacker’s payload. These interactions would be considered involuntary and do not require that the user actively subvert protections built into the vulnerable system.
Vulnerable system confidentiality: High: There is a total loss of confidentiality, resulting in all information within the Vulnerable System being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.
Vulnerable system integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the vulnerable system. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the vulnerable system.
Vulnerable system availability: None: There is no impact to availability within the Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 21 Jan 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-25.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade cvat and cvat-ai/cvat to 2.55.0.

Affected software

Product	Affected	Fixed in
cvat-aicvat	Affected >=2.2.0 <2.55.0	Fixed in 2.55.0
GitHubcvat-ai/cvat`pkg:github/cvat-ai/cvat`Other threats	Affected >=2.2.0 <2.55.0	Fixed in 2.55.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Organizations should upgrade all CVAT instances to version 2.55.0 or later, where the vulnerability is fixed. Until upgrading is possible, administrators should restrict user permissions to limit who can create or edit labels and upload SVG images, minimizing the risk of malicious content injection. Implement strict input validation and sanitization on all user-supplied data, especially labels and SVG uploads, to prevent script injection. Employ Content Security Policy (CSP) headers to reduce the impact of potential XSS by restricting script execution sources. Educate users about the risks of interacting with untrusted labels or images within CVAT. Monitor CVAT logs and user activity for unusual behavior indicative of exploitation attempts. If CVAT is exposed to the internet, consider placing it behind a web application firewall (WAF) configured to detect and block XSS payloads. Regularly audit and review annotation projects and labels for suspicious content. Finally, integrate CVAT usage within a broader security monitoring and incident response framework to quickly detect and respond to potential compromises.

Description

CVAT is an open source interactive video and image annotation tool for computer vision. In versions 2.2.0 through 2.54.0, an attacker is able to execute arbitrary JavaScript in a victim user's CVAT UI session, provided that they are able to create a maliciously crafted label in a CVAT task or project, then get the victim user to either edit that label, or view a shape that refers to that label; and/or get the victim user to upload a maliciously crafted SVG image when configuring a skeleton. This gives the attacker temporary access to all CVAT resources that the victim user can access. Version 2.55.0 fixes the issue.

Impact

The impact of CVE-2026-23516 is significant for organizations using vulnerable versions of CVAT for computer vision annotation tasks. Successful exploitation allows attackers to execute arbitrary JavaScript in the context of the victim user's session, potentially leading to session hijacking, data theft, unauthorized access to sensitive annotation projects, and manipulation or deletion of annotation data. This can compromise the integrity and confidentiality of valuable machine learning training data and related intellectual property. Since CVAT is often used in research, autonomous vehicle development, and AI model training, the exposure of such data could have downstream effects on AI model accuracy and organizational competitive advantage. The vulnerability requires user interaction but no authentication or privileges, increasing the risk in environments where multiple users share access or where attackers can trick users into interacting with malicious content. The temporary access gained can be leveraged for lateral movement within the organization’s infrastructure if CVAT is integrated with other systems. Although no exploits are known in the wild, the high CVSS score and ease of exploitation make timely patching critical to prevent potential attacks.

Summary

CVE-2026-23516 is a cross-site scripting (XSS) vulnerability affecting the open-source computer vision annotation tool CVAT, specifically versions 2.2.0 through 2.54.0. The flaw arises from improper sanitization of user-supplied input in labels and SVG images used within the CVAT UI. An attacker can craft malicious labels embedded with JavaScript or upload specially crafted SVG images when configuring skeletons. When a victim user views or edits these malicious labels or loads the SVG, the embedded script executes within their browser session. This execution context allows the attacker to hijack the victim's session and gain temporary access to all CVAT resources the victim can access, potentially exposing sensitive annotation data or project information. The vulnerability does not require any privileges or authentication on the attacker's part but does require user interaction (viewing or editing the malicious content). The issue is classified under CWE-83, indicating improper neutralization of script in attributes. The vulnerability was publicly disclosed on January 21, 2026, with a CVSS 4.0 base score of 8.6 (high severity), reflecting its ease of exploitation over the network and significant impact on confidentiality and integrity. The issue was resolved in CVAT version 2.55.0 by properly sanitizing inputs and preventing script injection in labels and SVG uploads. No known exploits have been reported in the wild to date.

CWE-83Improper Neutralization of Script in Attributes in a Web Page (opens in a new tab)
Variant weaknessOWASP Top 10 A05:2025: Injection (opens in a new tab)
The product does not neutralize or incorrectly neutralizes "javascript:" or other URIs from dangerous attributes within tags, such as onmouseover, onload, onerror, or style.
Implementation
Carefully check each input parameter against a rigorous positive specification (allowlist) defining the specific characters and format allowed. All input should be neutralized, not just parameters that the user is supposed to specify, but all data in the request, including tag attributes, hidden fields, cookies,…
Implementation · Output Encoding
Use and specify an output encoding that can be handled by the downstream component that is reading the output. Common encodings include ISO-8859-1, UTF-7, and UTF-8.
Implementation
With Struts, write all data from form beans with the bean's filter attribute set to true.
OWASP Cheat Sheets
Abuse Case (opens in a new tab)
Deserialization (opens in a new tab)
Cross Site Scripting Prevention (opens in a new tab)
DOM based XSS Prevention (opens in a new tab)
Injection Prevention (opens in a new tab)
OWASP ASVS 4.0.3
V1.5.1 (opens in a new tab)
V5.3.3 (opens in a new tab)
Attack patterns
XSS Targeting HTML Attributes (opens in a new tab)
XSS Targeting URI Placeholders (opens in a new tab)
DOM-Based XSS (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 27 Feb 2026, 08:42 UTC

WeaknessesCWE-83

Technical details

References

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