PYSEC-2026-1362

Vulnerability from pysec - Published: 2026-07-07 16:03 - Updated: 2026-07-07 17:24
VLAI
Details

Versions of the package fastapi-sso before 0.19.0 are vulnerable to Cross-site Request Forgery (CSRF) due to the improper validation of the OAuth state parameter during the authentication callback. While the get_login_url method allows for state generation, it does not persist the state or bind it to the user's session. Consequently, the verify_and_process method accepts the state received in the query parameters without verifying it against a trusted local value. This allows a remote attacker to trick a victim into visiting a malicious callback URL, which can result in the attacker's account being linked to the victim's internal account.

Severity
6.3 (Medium)
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:L/A:N
5.4 (Medium)
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N/E:P
Impacted products
Name purl
fastapi-sso pkg:pypi/fastapi-sso
Aliases
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "fastapi-sso",
        "purl": "pkg:pypi/fastapi-sso"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.19.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.10.0",
        "0.11.0",
        "0.12.0",
        "0.12.1",
        "0.12.2",
        "0.13.0",
        "0.13.1",
        "0.14.0",
        "0.14.1",
        "0.14.2",
        "0.15.0",
        "0.16.0",
        "0.17.0",
        "0.18.0",
        "0.2.1",
        "0.2.10",
        "0.2.11",
        "0.2.12",
        "0.2.13",
        "0.2.2",
        "0.2.3",
        "0.2.4",
        "0.2.5",
        "0.2.6",
        "0.2.7",
        "0.2.8",
        "0.2.9",
        "0.3.0",
        "0.4.0",
        "0.5.0",
        "0.5.1",
        "0.6.1",
        "0.6.2",
        "0.6.3",
        "0.6.4",
        "0.7.0",
        "0.7.1",
        "0.7.2",
        "0.7.3",
        "0.7.4",
        "0.8.0",
        "0.9.0",
        "0.9.1"
      ]
    }
  ],
  "aliases": [
    "CVE-2025-14546",
    "GHSA-hp6r-r9vc-q8wx"
  ],
  "details": "Versions of the package fastapi-sso before 0.19.0 are vulnerable to Cross-site Request Forgery (CSRF) due to the improper validation of the OAuth state parameter during the authentication callback. While the get_login_url method allows for state generation, it does not persist the state or bind it to the user\u0027s session. Consequently, the verify_and_process method accepts the state received in the query parameters without verifying it against a trusted local value. This allows a remote attacker to trick a victim into visiting a malicious callback URL, which can result in the attacker\u0027s account being linked to the victim\u0027s internal account.",
  "id": "PYSEC-2026-1362",
  "modified": "2026-07-07T17:24:07.655628Z",
  "published": "2026-07-07T16:03:13.588483Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-14546"
    },
    {
      "type": "WEB",
      "url": "https://github.com/tomasvotava/fastapi-sso/issues/266"
    },
    {
      "type": "WEB",
      "url": "https://github.com/tomasvotava/fastapi-sso/commit/6117d1a5ad498ba57d671e8a059ebe20db5abe02"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/tomasvotava/fastapi-sso"
    },
    {
      "type": "WEB",
      "url": "https://security.snyk.io/vuln/SNYK-PYTHON-FASTAPISSO-14386403"
    },
    {
      "type": "PACKAGE",
      "url": "https://pypi.org/project/fastapi-sso"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/advisories/GHSA-hp6r-r9vc-q8wx"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:L/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N/E:P",
      "type": "CVSS_V4"
    }
  ],
  "summary": "FastAPI SSP is vulnerable to Cross-site Request Forgery (CSRF) through improper OAuth parameter validation"
}



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  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.