Vulnerability-Lookup

GHSA-9FQ7-6G6P-G9RM

Vulnerability from github – Published: 2026-08-02 15:30 – Updated: 2026-08-02 15:30

Details

Better Auth relies on better-call, which uses the rou3 router library. In affected versions of rou3, paths are normalized by removing empty segments, so /path, //path, and ///path resolve to the same route. In Better Auth versions prior to 1.4.5 (which bundles the fixed rou3), this can allow attackers to bypass disabledPaths configuration and path-based rate limits by submitting requests with extra slashes in the URL path. The issue does not apply in deployments where the proxy or platform normalizes URLs by collapsing multiple slashes.

Severity

8.6 (High)


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

8.8 (High)


                  
                    CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N

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JSON

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{
  "affected": [],
  "aliases": [
    "CVE-2025-71399"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-20"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-02T13:16:52Z",
    "severity": "HIGH"
  },
  "details": "Better Auth relies on better-call, which uses the rou3 router library. In affected versions of rou3, paths are normalized by removing empty segments, so /path, //path, and ///path resolve to the same route. In Better Auth versions prior to 1.4.5 (which bundles the fixed rou3), this can allow attackers to bypass disabledPaths configuration and path-based rate limits by submitting requests with extra slashes in the URL path. The issue does not apply in deployments where the proxy or platform normalizes URLs by collapsing multiple slashes.",
  "id": "GHSA-9fq7-6g6p-g9rm",
  "modified": "2026-08-02T15:30:21Z",
  "published": "2026-08-02T15:30:21Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/better-auth/better-auth/security/advisories/GHSA-x732-6j76-qmhm"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-71399"
    },
    {
      "type": "WEB",
      "url": "https://github.com/better-auth/better-auth/commit/f60b43fa648399534507c9ac7db36d705b8874c3"
    },
    {
      "type": "WEB",
      "url": "https://www.vulncheck.com/advisories/better-auth-before-path-normalization-bypass-via-rou3"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ]
}

CVE-2025-71399 (GCVE-0-2025-71399)

Vulnerability from cvelistv5 – Published: 2026-08-02 12:15 – Updated: 2026-08-03 15:50

Title

Better Auth before 1.4.5 Path Normalization Bypass via rou3

Summary

Severity

8.8 (High)


                        
                          CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N

8.6 (High)


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

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-03 15:48 UTC

CWE

CWE-20 - Improper Input Validation

Assigner

VulnCheck mitre root

References

3 references

URL	Tags
https://github.com/better-auth/better-auth/securi…	vendor-advisory
https://github.com/better-auth/better-auth/commit…	patch
https://www.vulncheck.com/advisories/better-auth-…	third-party-advisory

Impacted products

1 product

Vendor	Product	Version
better-auth	better-auth	Affected: 0 , < 1.4.5 (semver) Unaffected: 1.4.5 (semver) cpe:2.3:a:better-auth:better-auth\/oauth-provider::::::node.js::*

Date Public

2025-12-15 00:00

Credits

goksan

Show details on NVD website

JSON

To clipboard

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                "id": "CVE-2025-71399",
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                  },
                  {
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                  }
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                "role": "CISA Coordinator",
                "timestamp": "2026-08-03T15:48:08.348859Z",
                "version": "2.0.3"
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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.

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.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.