CVE-2026-125336: Forge spoofing in X.509 name checks (high)

Summary

Forge (node-forge), a JavaScript TLS and certificate library, fails to enforce X.509 name constraints when verifying certificate chains, so a name-constrained certificate authority's leaf certificate can be accepted for names outside its permitted scope. An attacker who controls such a CA's private key, or can obtain an out-of-scope certificate, can remotely, without logging in, impersonate names outside the delegated namespace, including to forge.tls clients.

Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.

Read the original description

Forge (also called node-forge) is a native implementation of Transport Layer Security in JavaScript. Prior to 1.4.3, pki.verifyCertificateChain() in lib/x509.js does not decode or enforce the X.509 nameConstraints extension while validating certificate paths. A name-constrained certificate authority with a non-critical extension can therefore issue a leaf certificate with a subjectAltName dNSName or subject commonName outside a permitted subtree or inside an excluded subtree, and node-forge accepts the chain. Exploitation requires a name-constrained CA that chains to a trusted root and either its private key or the ability to obtain an out-of-scope certificate, allowing impersonation of names outside the delegated namespace, including against forge.tls clients. Chains without nameConstraints are not affected, and affected versions safely reject critical nameConstraints as unsupported rather than accepting them. This issue is fixed in version 1.4.3.

cve.now Index

24Pcve.now Index 24 of 100 · methodology v3 · provisional

Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
Exposure17/25No login or user action needed per the CVSS vector, reachable over the network without a login · Unknown: No advisory context yet
Reach?/20Unknown. No tracked technology or package matched
Severity7.4/10CVSS 7.4
No patch0/5No signal

What would change the score

Would score about 69 if added to CISA KEV
Would score about 64 if CISA's SSVC rates exploitation active
Would score about 29 if advisories confirm default setups are exposed

How the score works · Rankings

What to do

Upgrade to a fixed version: 1.4.3.

Check your systems with an agent

Paste this into a coding or ops agent. It checks your systems read-only and reports a table per asset.

Check whether my systems are affected by CVE-2026-125336 (Forge: X.509 nameConstraints not enforced by verifyCertificateChain()), using the cve.now data below.

Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only.

What cve.now has for CVE-2026-125336 (entry last updated 2026-11-10):
Affected:
- digitalbazaar forge: fixed in 1.4.3
Fixed versions: 1.4.3.
Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory.
CISA KEV: CVE-2026-125336 is not listed as of cve.now's last read.
This KEV status is for CVE-2026-125336 only. If you also check another CVE, look up its own KEV status; never assume it from this one.

How to check:
- Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory.

Verify against the linked advisories before concluding, and cite the date you read each one:
- https://github.com/digitalbazaar/forge/security/advisories/GHSA-3cc4-3294-vgjf
- https://github.com/digitalbazaar/forge/pull/1169
- https://github.com/digitalbazaar/forge/commit/6b23eae8beac316b6867bdb0e7ad7c2c959a97f6
- https://github.com/digitalbazaar/forge/commit/862aa5f630bdf40b0dfda408d6ac357bf35a7d6b
- https://github.com/digitalbazaar/forge/releases/tag/v1.4.3
Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing.

Entry: https://cve.now/CVE-2026-125336
For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example get_vulnerability with id CVE-2026-125336.

Timeline

Nov 10, 2026, 6:52 PM UTCCVE published
Nov 10, 2026, 8:54 PM UTCFirst seen by cve.now

Affected versions

digitalbazaar forge
fixed in 1.4.3

Evidence 7

Vendor advisory · 1

Establishes: Affected and fixed versions.

Advisory
GitHub · digitalbazaar/forge · Advisory GHSA-3cc4-3294-vgjf

CVE record · 2

Establishes: The identifier and description.

Record
CVE List · CVE-2026-125336
Record
NVD · CVE-2026-125336

Corrections

None so far.

Something wrong on this page? Report an error. Every fix is listed here.

Questions about CVE-2026-125336

Is CVE-2026-125336 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data

Which versions are affected by CVE-2026-125336?

forge: before 1.4.3.Source: cve.now feed data

How do I fix CVE-2026-125336?

Upgrade to a fixed version: 1.4.3.Source: cve.now feed data

Forge: X.509 nameConstraints not enforced by verifyCertificateChain()