GHSA-VM9R-H74P-HG97

Vulnerability from github – Published: 2026-03-31 23:09 – Updated: 2026-03-31 23:09
VLAI
Summary
jose vulnerable to untrusted JWK header key acceptance during signature verification
Details

Impact

A vulnerability in jose versions up to and including 0.3.5 could allow an unauthenticated, remote attacker to forge valid JWS/JWT tokens by using a key embedded in the JOSE header (jwk).

The vulnerability exists because key selection could treat header-provided jwk as a verification candidate even when that key was not present in the trusted key store. Since JOSE headers are untrusted input, an attacker could exploit this by creating a token payload, embedding an attacker-controlled public key in the header, and signing with the matching private key.

Applications using affected versions for token verification are impacted.

Patches

Upgrade to 0.3.5+1 or later.

Workarounds

Reject tokens where header jwk is present unless that jwk matches a key already present in the application's trusted key store.

Resources

Fix commit: fix: improved key resolution in JsonWebKeyStore

Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Show details on source website
To clipboard 

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 0.3.5"
      },
      "package": {
        "ecosystem": "Pub",
        "name": "jose"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.3.5+1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-34240"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-347"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-03-31T23:09:16Z",
    "nvd_published_at": "2026-03-31T16:16:33Z",
    "severity": "HIGH"
  },
  "details": "### Impact\n\nA vulnerability in `jose` versions up to and including `0.3.5` could allow an unauthenticated, remote attacker to forge valid JWS/JWT tokens by using a key embedded in the JOSE header (`jwk`).  \n\nThe vulnerability exists because key selection could treat header-provided `jwk` as a verification candidate even when that key was not present in the trusted key store. Since JOSE headers are untrusted input, an attacker could exploit this by creating a token payload, embedding an attacker-controlled public key in the header, and signing with the matching private key.  \n\nApplications using affected versions for token verification are impacted.\n\n### Patches\n\nUpgrade to `0.3.5+1` or later.\n\n### Workarounds\n\nReject tokens where header `jwk` is present unless that `jwk` matches a key already present in the application\u0027s trusted key store.\n\n### Resources\n\nFix commit: [fix: improved key resolution in JsonWebKeyStore](https://github.com/appsup-dart/jose/commit/b07799aac1f56a9a21483feac026272aab30cc5d)",
  "id": "GHSA-vm9r-h74p-hg97",
  "modified": "2026-03-31T23:09:16Z",
  "published": "2026-03-31T23:09:16Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/appsup-dart/jose/security/advisories/GHSA-vm9r-h74p-hg97"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-34240"
    },
    {
      "type": "WEB",
      "url": "https://github.com/appsup-dart/jose/commit/b07799aac1f56a9a21483feac026272aab30cc5d"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/appsup-dart/jose"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "jose vulnerable to untrusted JWK header key acceptance during signature verification"
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Detection rules are retrieved from Rulezet.