# PYSEC-2026-3: Two telnyx versions published containing credential harvesting malware

> Compromised telnyx library versions execute malware upon import, harvesting credentials and exfiltrating data to a remote server.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 27 Mar 2026

## What is PYSEC-2026-3?

PYSEC-2026-3 is a vulnerability in telnyx, published on 27 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

After an API token exposure from an exploited Trivy dependency,
two new releases of `telnyx` were uploaded to PyPI containing automatically activated malware,
 harvesting sensitive credentials and files, and exfiltrating to a remote API.

 Compromised versions execute code during importing the `telnyx` module through modifications in `_client.py`.

The code downloads the next stages from endpoints on the host 83.142.209[.]203, encoded in WAV files.
On Windows hosts, the malicious executable is placed in 
`%APPDATA%\Microsoft\Windows\Start Menu\Programs\Startup\msbuild.exe`
 for persistence and executed.
On other systems, the payload is a Python script.
 After executing it, generated artifacts are exfiltrated to 83.142.209[.]203.

 Version 4.87.1 contains a typo preventing the automated execution of the malicious code.

The code uses the encryption key observed in previous TeamPCP actions.
 The full compromise of exposed systems and all credentials reachable from them should be assumed. 
The credentials should be revoked/rotated, and the affected systems isolated
and analyzed against malicious actions and modifications.

The two versions have been removed from PyPI, and the project has been reinstated.

## Which versions are affected by PYSEC-2026-3?

1 open source package ship an affected version, including telnyx.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `telnyx` | PyPI | All versions | None |

## How do I fix PYSEC-2026-3?

No fix has been published for PYSEC-2026-3 yet. Limit exposure of the affected software until one is available.

## Is PYSEC-2026-3 being exploited?

There is no known exploitation of PYSEC-2026-3 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for PYSEC-2026-3 and fix it if it is affected.

What it is: PYSEC-2026-3 is a vulnerability in telnyx, published on 27 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of PYSEC-2026-3 in the wild and no public exploit code.

Affected packages and fixed versions:
- telnyx (PyPI): affected all versions; no fix listed

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/PYSEC-2026-3/ (Markdown: https://insights.sbomify.com/PYSEC-2026-3/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/PYSEC-2026-3

---
From sbomify Insights: https://insights.sbomify.com/PYSEC-2026-3/
Summaries are generated and may contain mistakes; the official description above is the record.