Forge: PKCS#12 MAC forgery and constant-key PBE via zero iteration count

Exploitation

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

CVSS

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

EPSS

• CVE-2026-118782: 0.13% estimated exploitation activity in the next 30 days; percentile 2.23 (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.

Summary forge.pkcs12.pkcs12FromAsn1() accepts a PKCS#12 MAC iteration count of zero (or less) from the input, and the PKCS#12 key derivation function then returns a constant key that does not depend on the password or salt. An attacker who does not know the password can modify a PKCS#12/PFX file and compute a MAC that verifies with any password; PKCS#12 PBE-encrypted private keys prepared the same way decrypt with any password. Fixed in node-forge 1.4.1.

Details `p12.pkcs12FromAsn1()` in `lib/pkcs12.js` reads the MAC iteration count (`MacData.iterations`) from the input and passes it to the PKCS#12 key derivation function `pki.pbe.generatePkcs12Key()` in `lib/pbe.js` (also exposed as `forge.pkcs12.generateKey()`) without checking that it is at least 1. The key derivation function (RFC 7292 Appendix B.2) runs its hash loop `iter` times. With an iteration count of 0 (or an empty or negative INTEGER), no hashing is done and the function returns the PKCS#12 diversifier ID byte…

Published by the source

30 Oct 2026, 23:02 UTC

Last modified by the source

30 Oct 2026, 23:15 UTC

Source last checked

31 Oct 2026, 06:00 UTC

1. Revision 2 · amended · 31 Oct 2026

   Amended from osv record GHSA-jc66-7q78-782g

2. Revision 1 · created · 30 Oct 2026

   Published from ghsa record GHSA-jc66-7q78-782g

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# Patch Next advisory brief: CVE-2026-118782

Advisory: Forge: PKCS#12 MAC forgery and constant-key PBE via zero iteration count
IDs: CVE-2026-118782, GHSA-jc66-7q78-782g
Record: https://patchnext.com/advisories/cve-2026-118782 (revision 2, source checked 31 Oct 2026, 06:00 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: node-forge 1.4.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm node-forge: affected < 1.4.1; fixed in 1.4.1

## 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-jc66-7q78-782g (GitHub-reviewed advisory GHSA-jc66-7q78-782g lists affected ranges: npm node-forge >=0 <=1.4.0)
- Verified: https://osv.dev/vulnerability/GHSA-jc66-7q78-782g (OSV record GHSA-jc66-7q78-782g lists affected ranges: npm node-forge >=0 <1.4.1 (fixed))

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