SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityDeferred

CVE-2025-53890

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.

CRITICAL 9.8EPSS 1.15%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (1.15%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

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.

CVSS 3.1
9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
1.15% probability · 65th percentile
CISA KEV
Not listed
Weakness
CWE-94
Source
security-advisories@github.com

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.