Vulnerability-Lookup

CVE-2026-9537 (GCVE-0-2026-9537)

Vulnerability from cvelistv5 – Published: 2026-07-17 15:29 – Updated: 2026-07-20 19:37

Title

Mojo::JWT versions before 1.02 for Perl verify HMAC signatures with a non-constant-time string comparison

Summary

Mojo::JWT versions before 1.02 for Perl verify HMAC signatures with a non-constant-time string comparison. The decode() method compares the supplied signature to the recomputed HMAC with Perl's eq operator, which stops at the first differing byte, so the comparison time varies with the number of matching leading bytes. A caller that decodes attacker supplied tokens leaks the expected signature through this timing variation, which can be aggregated over many requests to recover the signature and forge a token.

Severity

5.3 (Medium)


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

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-07-20 19:37 UTC

CWE

CWE-208 - Observable Timing Discrepancy

Assigner

CPANSec CNA under the redhat root

CNA scorecard C 64/100 over 273 records in the last 180 days details

References

2 references

URL	Tags
https://github.com/jberger/Mojo-JWT/commit/b8aefb…	patch
http://www.openwall.com/lists/oss-security/2026/0…

Impacted products

1 product

Vendor	Product	Version	CPE status
JBERGER	Mojo::JWT	Affected: 0 , < 1.02 (custom)	guessed

Show details on NVD website

JSON

To clipboard

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    "dateReserved": "2026-05-25T20:46:44.842Z",
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      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "perl-Mojo-JWT: verification of HMAC signatures with a non-constant-time string comparison",
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    "vulnrichment": {
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}

FKIE_CVE-2026-9537

Vulnerability from fkie_nvd - Published: 2026-07-17 16:17 - Updated: 2026-07-20 20:16

Severity

5.3 (Medium) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Summary

References

	URL	Tags
	9b29abf9-4ab0-4765-b253-1875cd9b441e	https://github.com/jberger/Mojo-JWT/commit/b8aefb846613e44b5b12bc170898ffd5b05094a2.patch
	af854a3a-2127-422b-91ae-364da2661108	http://www.openwall.com/lists/oss-security/2026/07/17/11

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "collectionURL": "https://cpan.org/modules",
          "defaultStatus": "unaffected",
          "packageName": "Mojo-JWT",
          "product": "Mojo::JWT",
          "programFiles": [
            "lib/Mojo/JWT.pm"
          ],
          "programRoutines": [
            {
              "name": "Mojo::JWT::decode"
            }
          ],
          "repo": "http://github.com/jberger/Mojo-JWT",
          "vendor": "JBERGER",
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            {
              "lessThan": "1.02",
              "status": "affected",
              "version": "0",
              "versionType": "custom"
            }
          ]
        }
      ],
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    }
  ],
  "id": "CVE-2026-9537",
  "lastModified": "2026-07-20T20:16:47.960",
  "metrics": {
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      {
        "cvssData": {
          "attackComplexity": "LOW",
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}

GHSA-3RP9-GQ85-W2MF

Vulnerability from github – Published: 2026-07-17 18:31 – Updated: 2026-07-20 21:31

Details

Mojo::JWT versions before 1.02 for Perl verify HMAC signatures with a non-constant-time string comparison.

The decode() method compares the supplied signature to the recomputed HMAC with Perl's eq operator, which stops at the first differing byte, so the comparison time varies with the number of matching leading bytes.

A caller that decodes attacker supplied tokens leaks the expected signature through this timing variation, which can be aggregated over many requests to recover the signature and forge a token.

Severity

5.3 (Medium)


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

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-9537"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-208"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-17T16:17:20Z",
    "severity": "MODERATE"
  },
  "details": "Mojo::JWT versions before 1.02 for Perl verify HMAC signatures with a non-constant-time string comparison.\n\nThe decode() method compares the supplied signature to the recomputed HMAC with Perl\u0027s eq operator, which stops at the first differing byte, so the comparison time varies with the number of matching leading bytes.\n\nA caller that decodes attacker supplied tokens leaks the expected signature through this timing variation, which can be aggregated over many requests to recover the signature and forge a token.",
  "id": "GHSA-3rp9-gq85-w2mf",
  "modified": "2026-07-20T21:31:43Z",
  "published": "2026-07-17T18:31:25Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-9537"
    },
    {
      "type": "WEB",
      "url": "https://github.com/jberger/Mojo-JWT/commit/b8aefb846613e44b5b12bc170898ffd5b05094a2.patch"
    },
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2026/07/17/11"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
      "type": "CVSS_V3"
    }
  ]
}

OPENSUSE-SU-2026:11450-1

Vulnerability from csaf_opensuse - Published: 2026-08-04 00:00 - Updated: 2026-09-17 17:18

Summary

perl-Mojo-JWT-1.20.0-2.1 on GA media

Severity

Moderate

Scope

1 vulnerability in this advisory, including CVE-2026-9537.

CVE-2026-9537

Recommended: 4 products

Open the full advisory

UBUNTU-CVE-2026-9537 (CVE-2026-9537)

Vulnerability from osv_ubuntu – Published: 2026-07-17 16:17 – Updated: 2026-07-29 07:53 – Source website

Details

Severity

5.3 (Medium)


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

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-9537	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-9537	REPORT
	https://lists.security.metacpan.org/cve-announce/…	REPORT

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{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libmojo-jwt-perl",
            "binary_version": "0.05-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:18.04:LTS",
        "name": "libmojo-jwt-perl",
        "purl": "pkg:deb/ubuntu/libmojo-jwt-perl@0.05-1?arch=source\u0026distro=bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.05-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libmojo-jwt-perl",
            "binary_version": "0.08-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "libmojo-jwt-perl",
        "purl": "pkg:deb/ubuntu/libmojo-jwt-perl@0.08-1?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.08-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libmojo-jwt-perl",
            "binary_version": "0.09-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "libmojo-jwt-perl",
        "purl": "pkg:deb/ubuntu/libmojo-jwt-perl@0.09-1?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.09-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libmojo-jwt-perl",
            "binary_version": "0.09-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "libmojo-jwt-perl",
        "purl": "pkg:deb/ubuntu/libmojo-jwt-perl@0.09-1?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.09-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libmojo-jwt-perl",
            "binary_version": "1.01-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "libmojo-jwt-perl",
        "purl": "pkg:deb/ubuntu/libmojo-jwt-perl@1.01-1?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.01-1"
      ]
    }
  ],
  "aliases": [],
  "details": "Mojo::JWT versions before 1.02 for Perl verify HMAC signatures with a non-constant-time string comparison. The decode() method compares the supplied signature to the recomputed HMAC with Perl\u0027s eq operator, which stops at the first differing byte, so the comparison time varies with the number of matching leading bytes. A caller that decodes attacker supplied tokens leaks the expected signature through this timing variation, which can be aggregated over many requests to recover the signature and forge a token.",
  "id": "UBUNTU-CVE-2026-9537",
  "modified": "2026-07-29T07:53:18Z",
  "published": "2026-07-17T16:17:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-9537"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-9537"
    },
    {
      "type": "REPORT",
      "url": "https://lists.security.metacpan.org/cve-announce/msg/41907805/"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-9537"
  ]
}

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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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Action not permitted

CVE-2026-9537 (GCVE-0-2026-9537)

FKIE_CVE-2026-9537

GHSA-3RP9-GQ85-W2MF

OPENSUSE-SU-2026:11450-1

UBUNTU-CVE-2026-9537 (CVE-2026-9537)

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