Integer Overflow in openssl-src

Exploitation

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

CVSS

5.9 · CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

• CVE-2021-23841: 7.41% estimated exploitation activity in the next 30 days; percentile 94.45 (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.

Calls to EVPCipherUpdate, EVPEncryptUpdate and EVPDecryptUpdate may overflow the output length argument in some cases where the input length is close to the maximum permissable length for an integer on the platform. In such cases the return value from the function call will be 1 (indicating success), but the output length value will be negative. This could cause applications to behave incorrectly or crash. OpenSSL versions 1.1.1i and below are affected by this issue. Users of these versions should upgrade to OpenSSL 1.1.1j. OpenSSL versions 1.0.2x and below are affected by this issue. However OpenSSL 1.0.2 is out of support and no longer receiving public updates. Premium support customers of OpenSSL 1.0.2 should upgrade to 1.0.2y. Other users should upgrade to 1.1.1j. Fixed in OpenSSL 1.1.1j (Affected 1.1.1-1.1.1i). Fixed in OpenSSL 1.0.2y (Affected 1.0.2-1.0.2x).

Published by the source

25 Aug 2021, 20:52 UTC

Last modified by the source

3 Apr 2023, 19:26 UTC

Source last checked

26 Oct 2026, 15:33 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-84rm-qf37-fgc2

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2021-23841

Advisory: Integer Overflow in openssl-src
IDs: CVE-2021-23841, GHSA-84rm-qf37-fgc2
Record: https://patchnext.com/advisories/cve-2021-23841 (revision 1, source checked 26 Oct 2026, 15:33 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.9)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: openssl-src 111.14.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- crates.io openssl-src: affected < 111.14.0; fixed in 111.14.0

## Suggested inspection (read-only)
- crates.io openssl-src: 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 openssl-src.
- 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-84rm-qf37-fgc2 (GitHub-reviewed advisory GHSA-84rm-qf37-fgc2 lists affected ranges: crates.io openssl-src >=0 <111.14.0)

Commands are suggestions: review each one before running it.