CVE-2025-54802: pyLoad CNL Blueprint allows Path Traversal through `dlc_path` which leads to Remote Code Execution (RCE)

Should you act?

Critical and remotely reachable

No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• Not in CISA KEV, but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
• EPSS 1.2%, percentile 68: FIRST’s model estimates a 1.2% chance of exploitation activity in the next 30 days, higher than 68% 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) <= 0.5.0b3.dev89, fixed in 0.5.0b3.dev90. Check your lockfile, including transitive dependencies.

What it is

pyLoad is the free and open-source Download Manager written in pure Python. In versions 0.5.0b3.dev89 and below, there is an opportunity for path traversal in pyLoad-ng CNL Blueprint via package parameter, allowing Arbitrary File Write which leads to Remote Code Execution (RCE). The addcrypted endpoint in pyload-ng suffers from an unsafe path construction vulnerability, allowing unauthenticated attackers to write arbitrary files outside the designated storage directory. This can be abused to overwrite critical system files, including cron jobs and systemd services, leading to privilege escalation and remote code execution as root. This issue is fixed in version 0.5.0b3.dev90.

From the GitHub advisory

Summary Path Traversal in pyLoad-ng CNL Blueprint via package parameter allows Arbitrary File Write leading to Remote Code Execution (RCE) The addcrypted endpoint in pyload-ng suffers from an unsafe path construction vulnerability, allowing unauthenticated attackers to write arbitrary files outside the designated storage directory. This can be abused to overwrite critical system files, including cron jobs and systemd services, leading to privilege escalation and remote code execution as root.

Details Endpoint: POST /addcrypted Issue: src/pyload/webui/app/blueprints/cnlblueprint.py

Vulnerable Code

PoC

Decoded payload:

Weakness type: CWE-22.

Product: pyload-ng (PyPI) · Assigned by: GitHub_M · Published: 2025-08-05

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Privileges required: none (no login)
• User interaction: none
• Scope: unchanged

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• 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): 1.20% probability of exploitation activity in the next 30 days; percentile 68.

Timeline

• 2025-08-04 — GitHub-reviewed advisory GHSA-48rp-jc79-2264 published (critical)
• 2025-08-05 — CVE record last updated
• 2025-08-05 — CVE record published by GitHub_M

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-48rp-jc79-2264 github.com
2. CVE.org record CVE-2025-54802 cve.org
3. NVD entry CVE-2025-54802 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
2. github.com github.com
3. github.com github.com

Critical PyPI advisories · Today’s Security Digest