Vulnerability-Lookup

CVE-2026-84376 (GCVE-0-2026-84376)

Vulnerability from cvelistv5 – Published: 2026-09-02 16:24 – Updated: 2026-09-04 02:44

Title

Astro: Authorization bypass from missing path-segment boundary check when stripping the configured base

Summary

Astro is a web framework for content-driven websites. Prior to 7.2.4, Astro stripped a configured non-root base path from request pathnames using a string-prefix check without verifying a path-segment boundary. With base "/app", a request to "/appX/admin" resolved internally to the protected "/admin" route while middleware observed "/appX/admin" in context.url.pathname. In applications that authorize base-prefixed routes by inspecting context.url.pathname, an unauthenticated remote attacker could bypass pathname-based middleware authorization and reach protected routes. This issue is fixed in version 7.2.4.

Severity

6.3 (Medium)


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

SSVC

Exploitation: none Automatable: yes Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-09-04 02:44 UTC

CWE

CWE-187 - Partial String Comparison

Assigner

GitHub_M mitre root

References

4 references

URL	Tags
https://github.com/withastro/astro/security/advis…	x_refsource_CONFIRM
https://github.com/withastro/astro/pull/17701	x_refsource_MISC
https://github.com/withastro/astro/commit/05763a0…	x_refsource_MISC
https://github.com/withastro/astro/releases/tag/a…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version	CPE status
withastro	astro	Affected: < 7.2.4	guessed

Show details on NVD website

JSON

To clipboard

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FKIE_CVE-2026-84376

Vulnerability from fkie_nvd - Published: 2026-09-02 17:18 - Updated: 2026-09-09 21:04

Severity

6.3 (Medium) - CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N

Summary

References

	URL	Tags
	security-advisories@github.com	https://github.com/withastro/astro/commit/05763a0884aabb1da78a2749d5bb9d41ae620527
	security-advisories@github.com	https://github.com/withastro/astro/pull/17701
	security-advisories@github.com	https://github.com/withastro/astro/releases/tag/astro@7.2.4
	security-advisories@github.com	https://github.com/withastro/astro/security/advisories/GHSA-376h-93r7-7g6f

Impacted products

	Vendor	Product	Version

JSON

To clipboard

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GHSA-376H-93R7-7G6F

Vulnerability from github – Published: 2026-09-08 21:26 – Updated: 2026-09-08 21:26

Summary

Astro: Authorization bypass from missing path-segment boundary check when stripping the configured base

Details

Summary

Astro stripped a configured base path from request pathnames using a string-prefix check that did not verify a path-segment boundary. With base: "/app", a request to /appX/admin was treated as being under the base and resolved internally to the /admin route, while middleware still observed the public pathname /appX/admin. Middleware that authorizes routes by inspecting context.url.pathname could therefore be bypassed.

Impact

An unauthenticated remote attacker can bypass pathname-based middleware authorization in applications that:

Configure a non-root base.
Protect base-prefixed routes in middleware using context.url.pathname.

Because routing and middleware resolved different effective pathnames, a request such as /appX/admin (or other single-character extensions like /app2/admin or /app-/admin) reached the protected /admin route without passing the middleware check that guards /app/admin. Astro's authentication guide demonstrates protecting routes in middleware via context.url.pathname, so this is a reasonable and expected pattern.

Affected versions

astro <= 7.2.3.

Patches

Fixed in astro 7.2.4. Base stripping now requires the pathname to equal the base without its trailing slash, or to be followed by a /, so a prefix that does not end on a path-segment boundary is no longer treated as being under the base. Routing and context.url.pathname now resolve the same pathname.

Workarounds

Upgrade to astro 7.2.4 or later. As a mitigation before upgrading, avoid relying solely on prefix checks of context.url.pathname for authorization, or reject requests whose pathname does not begin with the configured base followed by a path-segment boundary.

Credits

Reported by @Ryoga-exe.

Severity

6.3 (Medium)


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

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{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 7.2.3"
      },
      "package": {
        "ecosystem": "npm",
        "name": "astro"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "7.2.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-84376"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-187"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-09-08T21:26:02Z",
    "nvd_published_at": "2026-09-02T17:18:00Z",
    "severity": "MODERATE"
  },
  "details": "## Summary\n\nAstro stripped a configured `base` path from request pathnames using a string-prefix check that did not verify a path-segment boundary. With `base: \"/app\"`, a request to `/appX/admin` was treated as being under the base and resolved internally to the `/admin` route, while middleware still observed the public pathname `/appX/admin`. Middleware that authorizes routes by inspecting `context.url.pathname` could therefore be bypassed.\n\n## Impact\n\nAn unauthenticated remote attacker can bypass pathname-based middleware authorization in applications that:\n\n- Configure a non-root `base`.\n- Protect base-prefixed routes in middleware using `context.url.pathname`.\n\nBecause routing and middleware resolved different effective pathnames, a request such as `/appX/admin` (or other single-character extensions like `/app2/admin` or `/app-/admin`) reached the protected `/admin` route without passing the middleware check that guards `/app/admin`. Astro\u0027s authentication guide demonstrates protecting routes in middleware via `context.url.pathname`, so this is a reasonable and expected pattern.\n\n## Affected versions\n\n`astro` \u003c= 7.2.3.\n\n## Patches\n\nFixed in `astro` 7.2.4. Base stripping now requires the pathname to equal the base without its trailing slash, or to be followed by a `/`, so a prefix that does not end on a path-segment boundary is no longer treated as being under the base. Routing and `context.url.pathname` now resolve the same pathname.\n\n## Workarounds\n\nUpgrade to `astro` 7.2.4 or later. As a mitigation before upgrading, avoid relying solely on prefix checks of `context.url.pathname` for authorization, or reject requests whose pathname does not begin with the configured base followed by a path-segment boundary.\n\n## Credits\n\nReported by @Ryoga-exe.",
  "id": "GHSA-376h-93r7-7g6f",
  "modified": "2026-09-08T21:26:02Z",
  "published": "2026-09-08T21:26:02Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/withastro/astro/security/advisories/GHSA-376h-93r7-7g6f"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-84376"
    },
    {
      "type": "WEB",
      "url": "https://github.com/withastro/astro/pull/17701"
    },
    {
      "type": "WEB",
      "url": "https://github.com/withastro/astro/commit/05763a0884aabb1da78a2749d5bb9d41ae620527"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/withastro/astro"
    },
    {
      "type": "WEB",
      "url": "https://github.com/withastro/astro/releases/tag/astro@7.2.4"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Astro: Authorization bypass from missing path-segment boundary check when stripping the configured base"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

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Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

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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CVE-2026-84376 (GCVE-0-2026-84376)

FKIE_CVE-2026-84376

GHSA-376H-93R7-7G6F

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