In RubyGem excon, interrupted Persistent Connections May Leak Response Data

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

5.8 · CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:N/A:N

EPSS

• CVE-2019-16779: 1.66% estimated exploitation activity in the next 30 days; percentile 76.72 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact 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. Patches The problem has been patched in 0.71.0, users should upgrade to this or a newer version (if one exists). Workarounds Users can workaround the problem by disabling persistent connections, though this may cause performance implications. References See the patch for further details. For more information If you have any questions or comments about this advisory: Open an issue in excon/issues Email us at geemus+github@gmail.com

Published by the source

16 Dec 2019, 19:30 UTC

Last modified by the source

4 May 2023, 19:47 UTC

Source last checked

26 Oct 2026, 15:47 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-q58g-455p-8vw9

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# Patch Next advisory brief: CVE-2019-16779

Advisory: In RubyGem excon, interrupted Persistent Connections May Leak Response Data
IDs: CVE-2019-16779, GHSA-q58g-455p-8vw9
Record: https://patchnext.com/advisories/cve-2019-16779 (revision 1, source checked 26 Oct 2026, 15:47 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.8)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: excon 0.71.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- RubyGems excon: affected < 0.71.0; fixed in 0.71.0

## Suggested inspection (read-only)
- RubyGems excon: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on excon.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-q58g-455p-8vw9 (GitHub-reviewed advisory GHSA-q58g-455p-8vw9 lists affected ranges: RubyGems excon >=0 <0.71.0)

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