Forge: TLS client crash on an unsupported ServerHello compression method

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

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Summary A `forge.tls` client accepts any compression method in the ServerHello, although it only offers no compression. An unknown method makes `connection.process()` throw an uncaught `Error` when the client handles ServerHelloDone, before the server is authenticated. A malicious server or an on-path attacker can use this to terminate a Node.js process. Fixed in node-forge 1.4.3.

Details The client's ClientHello offers only the `null` compression method. `tls.parseHelloMessage()` in `lib/tls.js` stores the ServerHello's `compression_method` for the client without checking it (the code has a `TODO: handle compression methods`). When the client handles ServerHelloDone it calls `tls.createConnectionState()`, which throws `Error('Unsupported compression algorithm.')` for any method other than `null` (0) and `deflate` (1). The exception propagates out of `connection.process()`. The ServerHello isn't authenticated until the server's Finished message, so an on-path attacker can…

Published by the source

10 Nov 2026, 21:17 UTC

Last modified by the source

10 Nov 2026, 21:30 UTC

Source last checked

11 Nov 2026, 06:00 UTC

1. Revision 2 · amended · 11 Nov 2026

   Amended from osv record GHSA-w4xr-hqv8-ch44

2. Revision 1 · created · 10 Nov 2026

   Published from ghsa record GHSA-w4xr-hqv8-ch44

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# Patch Next advisory brief: CVE-2026-125332

Advisory: Forge: TLS client crash on an unsupported ServerHello compression method
IDs: CVE-2026-125332, GHSA-w4xr-hqv8-ch44
Record: https://patchnext.com/advisories/cve-2026-125332 (revision 2, source checked 11 Nov 2026, 06:00 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: node-forge 1.4.3. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm node-forge: affected < 1.4.3; fixed in 1.4.3

## Suggested inspection (read-only)
- `npm ls node-forge --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## 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 node-forge.
- 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-w4xr-hqv8-ch44 (GitHub-reviewed advisory GHSA-w4xr-hqv8-ch44 lists affected ranges: npm node-forge >=0 <=1.4.2)
- Verified: https://osv.dev/vulnerability/GHSA-w4xr-hqv8-ch44 (OSV record GHSA-w4xr-hqv8-ch44 lists affected ranges: npm node-forge >=0 <1.4.3 (fixed))

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