VulnerabilityPublished 10 Mar 2026

CVE-2026-30974: 9001 copyparty · Cross-site Scripting

Affects 9001 copypartySource CVE Database V5

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Not known to be exploited · CVSS 4.6 Medium : upgrade to 1.20.11 when convenient.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 3.1 base score

4.6Medium

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

EPSS: 0.3% chance of exploitation in 30 days – higher than 27% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 1.20.11

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: Low
User Interaction: Required
Scope: Unchanged
Confidentiality: Low
Integrity: Low
Availability: None

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

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, 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: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 10 Mar 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 30 Oct 2026.

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.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity 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 copyparty and 9001/copyparty to 1.20.11.

Affected software

Product	Affected	Fixed in
9001copyparty	Affected <1.20.11	Fixed in 1.20.11
GitHub9001/copyparty`pkg:github/9001/copyparty`Other threats	Affected <1.20.11	Fixed in 1.20.11

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

AI-suggested

Upgrade copyparty to version 1.20.11 or later, where the vulnerability is fixed by applying the 'nohtml' option to SVG files.
Restrict write permissions strictly to trusted users to reduce the risk of malicious SVG uploads.
Implement file upload validation to block or sanitize SVG files containing scripts before they are accepted.
Educate users to be cautious when opening SVG files from untrusted sources within the file server environment.
Consider disabling SVG file support if not required.
Monitor server logs for unusual upload activity or access patterns to detect potential exploitation attempts.
Employ Content Security Policy (CSP) headers if possible to restrict script execution contexts in browsers accessing the copyparty server.
Regularly audit user permissions and uploaded content for suspicious files.

Description

CVE-2026-30974 is a medium-severity cross-site scripting (XSS) vulnerability in copyparty versions prior to 1.20.11. The issue arises because the 'nohtml' configuration option, designed to block JavaScript execution in user-uploaded HTML files, did not apply to SVG images. This allows a user with write permissions to upload an SVG containing embedded JavaScript, which executes in the context of any user who opens the SVG file. Exploitation requires user interaction and write permissions but does not require elevated privileges beyond that. The vulnerability impacts confidentiality and integrity but not availability. It has been fixed in version 1.20.11.

Impact

The primary impact of this vulnerability is on the confidentiality and integrity of user sessions and data accessed via the copyparty file server. An attacker who can upload malicious SVG files can execute arbitrary JavaScript in the context of other users who open these files, potentially stealing authentication tokens, cookies, or other sensitive information. This could lead to unauthorized actions performed on behalf of victims, data leakage, or manipulation of the user interface. Since exploitation requires write permissions and user interaction, the risk is limited to environments where multiple users have upload rights and access to the same files. Availability is not affected. Organizations using copyparty in shared or multi-user environments, especially where user permissions are not tightly controlled, face increased risk. The medium CVSS score indicates moderate risk but should not be underestimated in sensitive deployments.

CWE-79Improper Neutralization of Input During Web Page Generation (Cross-site Scripting) (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #1OWASP Top 10 A05:2025: Injection (opens in a new tab)
The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Implementation · Architecture and Design
Understand the context in which your data will be used and the encoding that will be expected. This is especially important when transmitting data between different components, or when generating outputs that can contain multiple encodings at the same time, such as web pages or multi-part mail messages.
Architecture and Design · Implementation · Attack Surface Reduction
Understand all the potential areas where untrusted inputs can enter your software: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide…
OWASP Cheat Sheets
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)
Abuse Case (opens in a new tab)
Deserialization (opens in a new tab)
OWASP ASVS 4.0.3
V5.3.3 (opens in a new tab)
V1.5.1 (opens in a new tab)
Attack patterns
XSS Using MIME Type Mismatch (opens in a new tab)
DOM-Based XSS (opens in a new tab)
Reflected XSS (opens in a new tab)
Stored XSS (opens in a new tab)
Cross-Site Scripting (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 17 Mar 2026, 19:06 UTC

WeaknessesCWE-79

Technical details

References

Community reviews

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