# CVE-2026-123816: pyLoad: Authentication bypass in API key validation (check_apikey cache)


- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 9 Nov 2026
- **Updated:** 10 Nov 2026
- **Also known as:** GHSA-r44w-v6gf-x3p6

## What is CVE-2026-123816?

CVE-2026-123816 is a high-severity vulnerability in pyload, published on 9 Nov 2026. 

### Official description

pyLoad is a free and open-source download manager written in Python. Prior to 0.5.0b3.dev101, Api.check_apikey caches successful validation in self._apikey_cache using only the attacker-controlled key_id. After a legitimate key populates the cache, a forged API key with the same key_id reaches the cache-hit path without comparing apikey[-43:] to the stored hash through hmac.compare_digest. Key identifiers are small sequential integers, so an unauthenticated remote attacker can enumerate an active identifier and inherit the cached key owner's permissions during the 300-second cache lifetime. This issue is fixed in version 0.5.0b3.dev101.

Weakness: CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2026-123816?

1 open source package ship an affected version, including pyload-ng.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `pyload-ng` | PyPI | All versions | 0.5.0b3.dev101 |

## How do I fix CVE-2026-123816?

Upgrade pyload-ng to 0.5.0b3.dev101 or later.

## Is CVE-2026-123816 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-123816 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-123816 and fix it if it is affected.

What it is: CVE-2026-123816 is a high-severity vulnerability in pyload, published on 9 Nov 2026. 
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-123816 exists.

Affected packages and fixed versions:
- pyload-ng (PyPI): affected all versions; fixed in 0.5.0b3.dev101

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-123816/ (Markdown: https://insights.sbomify.com/CVE-2026-123816/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-123816
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-123816
- OSV: https://osv.dev/vulnerability/CVE-2026-123816

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-123816/
Summaries are generated and may contain mistakes; the official description above is the record.