CVE-2025-53890 pyLoad vulnerable to remote code execution through js2py onCaptchaResult
Unauthenticated attackers can execute arbitrary code via unsafe JavaScript evaluation in pyLoad's CAPTCHA processing, leading to full system compromise.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-53890?
CVE-2025-53890 is a critical code injection vulnerability in pyload, published on 14 Jul 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-94
Which versions are affected by CVE-2025-53890?
3 open source packages ship an affected version, including pyload-ng.
| Package | Affected | Fixed in |
|---|---|---|
pyload-ng PyPI | All versions | 0.20 |
pyload-ng PyPI | All versions | 0.20 |
pyload-ng PyPI | All versions | 0.20 |
How do I fix CVE-2025-53890?
Upgrade pyload-ng to 0.20 or later.
Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.
Is CVE-2025-53890 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-53890 exists.
Sources
Also known as GHSA-8w3f-4r8f-pf53, PYSEC-2026-496.