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NVD / CVE Program· CNA GitHub_M

CVE-2026-32109: Copyparty has unexpected JavaScript execution via crafted URL to folder with `.prologue.html`

Noroxi assessment

Priority: Monitor (action score 17/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.18% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. A user must open a link or visit a page. Special conditions such as timing or configuration are required.
  • Fixed version: 9001 copyparty 1.20.12.

Low priority for now. Upgrade to 9001 copyparty 1.20.12 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

MediumCVSS 4.4 · v3.1—No exploit Fix available
Published
Mar 11, 2026
Updated
Jun 17, 2026
EPSS
0.1% · 8th percentile

Report tools

JSON

Action score

17

Monitor

Low priority for now.

CVSS
17 / 40 · 4.4 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
4.4
CNA · GitHub_M
3.7
0.7 point gap

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
9001copyparty

Limit the impact of XSS

This is a cross-site scripting (XSS) vulnerability. A well-configured Content-Security-Policy doesn't fix it, but greatly reduces its impact. Check your site's CSP and other security headers for free.

Check security headers

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • 9001 copypartybefore 1.20.12

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • 9001 copyparty

    • < 1.20.12affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
PyPIcopypartybefore 1.20.121.20.12

Same product

9001: all records

Other highest-scoring records for the same primary product.

  • CVE-2023-37474Path traversal in copyparty
    43Plan
  • CVE-2023-41471Cross Site Scripting vulnerability in copyparty before 1.9.2 allows a local attacker to execute arbitrary code via a crafted payload to the
    31Monitor
  • CVE-2025-54796Copyparty is vulnerable to Regex Denial of Service (ReDoS) attacks through "Recent Uploads" page
    30Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-30974Mar 10, 2026 · Copyparty volflag `nohtml` did not block javascript in svg files
    21Monitor
  • ← EarlierCVE-2026-32108Mar 11, 2026 · Copyparty ftp/sftp: Sharing a single file did not fully restrict source-folder access
    9Monitor
  • Later →CVE-2026-70657Aug 18, 2026 · Copyparty: file/dirkey confusion
    17Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
9001 copyparty1.20.12 · descriptionVendor (CNA)
PyPI:copyparty1.20.12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2023-41471194 days apartCross Site Scripting vulnerability in copyparty before 1.9.2 allows a local attacker to execute arbitrary code via a crafted payload to the
    31Monitor
  • CVE-2025-54589223 days apartcopyparty Reflected XSS via Filter Parameter
    25Monitor
  • CVE-2026-2794814 days apartCopyparty vulnerable to eflected cross-site scripting via setck parameter
    24Monitor
  • CVE-2025-54423226 days apartcopyparty has a DOM-Based XSS vulnerability when displaying multimedia metadata
    24Monitor
  • CVE-2025-27145380 days apartcopyparty renders unsanitized filenames as HTML when user uploads empty files
    24Monitor
  • CVE-2026-309741 days apartCopyparty volflag `nohtml` did not block javascript in svg files
    21Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • A user must open a link or visit a page.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
low · data can be read
Integrity
low · data or configuration can be modified
Availability
none

Impact can extend beyond the vulnerable component (scope changes).

Attack vector
Network
Attack complexity
High
Privileges required
Low
User interaction
Required
Scope
Changed
Confidentiality impact
Low
Integrity impact
Low
Availability impact
None

Weakness class (CWE)

CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

CVSS vector

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

nvd-primary

Root cause

User content is inserted into the page as HTML. The browser interprets the content as code rather than data.

The bug in code

The whole CWE-79 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

ts
commentEl.innerHTML = comment.body;

Fixed

ts
commentEl.textContent = comment.body;

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records