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High

Forge has signature forgery in Ed25519 due to missing S > L check

Type: advisorySources: OSV

Forge (also called `node-forge`) is a native implementation of Transport Layer Security in JavaScript. Prior to version 1.4.0, Ed25519 signature verification accepts forged non-canonical signatures where the scalar S is not reduced modulo the group order (`S >= L`). A valid signature and its `S + L` variant both verify in forge, while Node.js `crypto.verify` (OpenSSL-backed) rejects the `S + L` variant, as defined by the specification. This class of signature malleability has been exploited in practice to bypass authentication and authorization logic (see CVE-2026-25793, CVE-2022-35961). Applications relying on signature uniqueness (i.e., dedup by signature bytes, replay tracking, signed-object canonicalization checks) may be bypassed. Version 1.4.0 patches the issue.

Products
Not specified
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2026-33895
Confirmed fixed CVEs
Not specified
Updated in this feed
8 Nov 2026, 02:04 UTC · Revision 1

Source evidence

Forge has signature forgery in Ed25519 due to missing S > L check

core-osv · Original source

Published 27 Mar 2026, 20:47 UTC

Forge (also called `node-forge`) is a native implementation of Transport Layer Security in JavaScript. Prior to version 1.4.0, Ed25519 signature verification accepts forged non-canonical signatures where the scalar S is not reduced modulo the group order (`S >= L`). A valid signature and its `S + L` variant both verify in forge, while Node.js `crypto.verify` (OpenSSL-backed) rejects the `S + L` variant, as defined by the specification. This class of signature malleability has been exploited in practice to bypass authentication and authorization logic (see CVE-2026-25793, CVE-2022-35961). Applications relying on signature uniqueness (i.e., dedup by signature bytes, replay tracking, signed-object canonicalization checks) may be bypassed. Version 1.4.0 patches the issue.

osv:CVE-2026-33895
Complete source record
{
  "id": "c8ae56fcd3dd4a89d05a712f2a8408865b082b32215b55e4327c93741137b666",
  "url": "https://osv.dev/vulnerability/CVE-2026-33895",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Forge has signature forgery in Ed25519 due to missing S > L check",
    "summary": "Forge (also called `node-forge`) is a native implementation of Transport Layer Security in JavaScript. Prior to version 1.4.0, Ed25519 signature verification accepts forged non-canonical signatures where the scalar S is not reduced modulo the group order (`S >= L`). A valid signature and its `S + L` variant both verify in forge, while Node.js `crypto.verify` (OpenSSL-backed) rejects the `S + L` variant, as defined by the specification. This class of signature malleability has been exploited in practice to bypass authentication and authorization logic (see CVE-2026-25793, CVE-2022-35961). Applications relying on signature uniqueness (i.e., dedup by signature bytes, replay tracking, signed-object canonicalization checks) may be bypassed. Version 1.4.0 patches the issue.",
    "evidence": "osv:CVE-2026-33895",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-33895",
      "aliases": [
        "CVE-2026-33895",
        "GHSA-q67f-28xg-22rw"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/digitalbazaar/forge",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "bdecf11571c9f1a487cc0fe72fe78ff6dfa96b85"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:digitalbazaar:forge:*:*:*:*:*:node.js:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "last_affected": "1.3.3"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "range": [
                      {
                        "fixed": "bdecf11571c9f1a487cc0fe72fe78ff6dfa96b85"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
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            "v1.3.2",
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          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-33895.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:53.133743074Z",
      "provider": "osv",
      "references": [
        "https://datatracker.ietf.org/doc/html/rfc8032#section-8.4",
        "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33895.json",
        "https://access.redhat.com/errata/RHSA-2026:13826",
        "https://access.redhat.com/errata/RHSA-2026:24761",
        "https://access.redhat.com/errata/RHSA-2026:34342",
        "https://access.redhat.com/errata/RHSA-2026:9742",
        "https://access.redhat.com/security/cve/CVE-2026-33895",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33895.json",
        "https://github.com/digitalbazaar/forge/security/advisories/GHSA-q67f-28xg-22rw",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-33895",
        "https://bugzilla.redhat.com/show_bug.cgi?id=2452457",
        "https://github.com/digitalbazaar/forge/commit/bdecf11571c9f1a487cc0fe72fe78ff6dfa96b85"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-347"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33895.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-33895",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 521612,
  "published_at": "2026-03-27T20:47:54.492+00:00"
}