---
title: "CVE-2025-53890: pyLoad vulnerable to XSS through insecure CAPTCHA"
url: https://erroneo.us/security/cve/CVE-2025-53890/
description: "CVE-2025-53890 (pyload-ng (PyPI)): pyload is an open-source Download Manager written in pure Python. An unsafe JavaScript evaluation vulnerability in…"
type: vulnerability-record
section: "Security Digest"
date_published: 2025-07-14
date_modified: 2025-07-15
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2025-53890"
kev: false
cvss: 9.8
epss: 0.01298
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2025-53890: pyLoad vulnerable to XSS through insecure CAPTCHA

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Not in CISA KEV , but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 1.3% , percentile 70: FIRST’s model estimates a 1.3% chance of exploitation activity in the next 30 days, higher than 70% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes pyload-ng (PyPI) < 0.20, fixed in 0.20 . Check your lockfile, including transitive dependencies.

## What it is

pyload is an open-source Download Manager written in pure Python. An unsafe JavaScript evaluation vulnerability in pyLoad’s CAPTCHA processing code allows unauthenticated remote attackers to execute arbitrary code in the client browser and potentially the backend server. Exploitation requires no user interaction or authentication and can result in session hijacking, credential theft, and full system remote code execution. Commit 909e5c97885237530d1264cfceb5555870eb9546, the patch for the issue, is included in version 0.5.0b3.dev89.

## Affected packages

- PyPI `pyload-ng` < 0.20 → fixed: 0.20

## Affected products (CVE record)

- pyload pyload: < 0.5.0b3.dev89

## Severity

- GitHub_M CVSS 3.1: 9.8 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`
- GitHub CVSS 3.1: 9.8 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 1.30% probability of exploitation activity in the next 30 days; percentile 70.

## Sources

- [GitHub Advisory GHSA-8w3f-4r8f-pf53](https://github.com/advisories/GHSA-8w3f-4r8f-pf53)
- [CVE.org record CVE-2025-53890](https://www.cve.org/CVERecord?id=CVE-2025-53890)
- [NVD entry CVE-2025-53890](https://nvd.nist.gov/vuln/detail/CVE-2025-53890)
- [github.com](https://github.com/pyload/pyload/security/advisories/GHSA-8w3f-4r8f-pf53)
- [github.com](https://github.com/pyload/pyload/pull/4586)
- [github.com](https://github.com/pyload/pyload/commit/909e5c97885237530d1264cfceb5555870eb9546)

---
Source page: https://erroneo.us/security/cve/CVE-2025-53890/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt