CVE-2026-32109: Copyparty is a portable file server. Prior to 1.20.12, if an attacker has been given both read- and write-permissions to the server, they can upload a...

Description

Copyparty is a portable file server. Prior to 1.20.12, if an attacker has been given both read- and write-permissions to the server, they can upload a malicious file with the filename .prologue.html and then craft a link to potentially execute arbitrary JavaScript in the victim's context. Note that it is intended behavior that the JavaScript would execute if the target clicks a link to the HTML file itself; "https://example.com/foo/.prologue.html". The vulnerability is that "https://example.com/foo/?b" would also evaluate the file, making the behavior unexpected. There are existing preventative measures (strict SameSite cookies) which makes it harder to leverage this vulnerability in an attack; in order to gain control of the target's authenticated session, the link must be clicked from a page served by the server itself -- most likely by editing an existing resource, which would require additional access permissions. Finally, for this attack to be successful, the attacker's target must click the specific crafted link given by the attacker. This vulnerability is not activated by normally browsing the web-UI on the server. This vulnerability is fixed in 1.20.12.

Metrics

CVSS 3.1

4.4/10

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

EPSS Probability

0.16%

5.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-79

Affected Software

Vendor	Product	Versions
9001	Copyparty	< 1.20.12

References

https://github.com/9001/copyparty/security/advisories/GHSA-rcp6-88mm-9vgfVendor Advisory

Timeline

Published: Mar 11, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-32109?

Copyparty is a portable file server. Prior to 1.20.12, if an attacker has been given both read- and write-permissions to the server, they can upload a malicious file with the filename .prologue.html and then craft a link to potentially execute arbitrary JavaScript in the victim's context. Note that it is intended behavior that the JavaScript would execute if the target clicks a link to the HTML file itself; "https://example.com/foo/.prologue.html". The vulnerability is that "https://example.com/foo/?b" would also evaluate the file, making the behavior unexpected. There are existing preventative measures (strict SameSite cookies) which makes it harder to leverage this vulnerability in an attack; in order to gain control of the target's authenticated session, the link must be clicked from a page served by the server itself -- most likely by editing an existing resource, which would require additional access permissions. Finally, for this attack to be successful, the attacker's target must click the specific crafted link given by the attacker. This vulnerability is not activated by normally browsing the web-UI on the server. This vulnerability is fixed in 1.20.12.

How severe is CVE-2026-32109?

CVE-2026-32109 has a CVSS score of 4.4/10 (MEDIUM severity). The EPSS model estimates a 0.16% probability of exploitation in the next 30 days.

How do I fix CVE-2026-32109?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

How Strix Helps

Related CVEs from 2026

View all 2026CVEs →