StringIO buffer overread vulnerability

Exploitation

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

CVSS 4.0

9.3 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N · score source

EPSS

• CVE-2024-27280: 2.36% estimated exploitation activity in the next 30 days; percentile 83.81 (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.

An issue was discovered in StringIO 3.0.1, as distributed in Ruby 3.0.x through 3.0.6 and 3.1.x through 3.1.4. The ungetbyte and ungetc methods on a StringIO can read past the end of a string, and a subsequent call to StringIO.gets may return the memory value. This vulnerability is not affected StringIO 3.0.3 and later, and Ruby 3.2.x and later. We recommend to update the StringIO gem to version 3.0.3 or later. In order to ensure compatibility with bundled version in older Ruby series, you may update as follows instead: For Ruby 3.0 users: Update to stringio 3.0.1.1 For Ruby 3.1 users: Update to stringio 3.1.0.2 You can use gem update stringio to update it. If you are using bundler, please add gem "stringio", "= 3.0.1.2" to your Gemfile.

Published by the source

25 Mar 2024, 19:36 UTC

Last modified by the source

4 Nov 2025, 19:46 UTC

Source last checked

26 Oct 2026, 15:51 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-v5h6-c2hv-hv3r

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# Patch Next advisory brief: CVE-2024-27280

Advisory: StringIO buffer overread vulnerability
IDs: CVE-2024-27280, GHSA-v5h6-c2hv-hv3r
Record: https://patchnext.com/advisories/cve-2024-27280 (revision 1, source checked 26 Oct 2026, 15:51 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 9.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: stringio 3.0.1.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- RubyGems stringio: affected < 3.0.1.1; fixed in 3.0.1.1

## Suggested inspection (read-only)
- RubyGems stringio: 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 stringio.
- 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-v5h6-c2hv-hv3r (GitHub-reviewed advisory GHSA-v5h6-c2hv-hv3r lists affected ranges: RubyGems stringio >=0 <3.0.1.1)

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