GCVE Workshop - 22 September 2026 (14:00-18:00), Luxembourg Before The Vulnopticon Conference - Registration

BREW-CLOUDFORMATION-CLI-… (GHSA-PX8H-6QXV-M22Q)

Vulnerability from osv_homebrew – Published: 2026-08-13 16:40 – Updated: 2026-09-17 17:52 – Source website
VLAI
Summary
Incorrect parsing of nameless cookies leads to __Host- cookies bypass
Details

Browsers may allow "nameless" cookies that look like =value instead of key=value. A vulnerable browser may allow a compromised application on an adjacent subdomain to exploit this to set a cookie like =__Host-test=bad for another subdomain.

Werkzeug <= 2.2.2 will parse the cookie =__Host-test=bad as __Host-test=bad. If a Werkzeug application is running next to a vulnerable or malicious subdomain which sets such a cookie using a vulnerable browser, the Werkzeug application will see the bad cookie value but the valid cookie key.

Severity
2.6 (Low)
CVSS:3.1/AV:A/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:N
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "fix": "bump",
        "range_state": "fixed",
        "resource": "werkzeug",
        "resource_purl": "pkg:pypi/werkzeug@3.1.8",
        "upstream_fixed_in": "2.2.3"
      },
      "package": {
        "ecosystem": "Homebrew",
        "name": "cloudformation-cli",
        "purl": "pkg:brew/cloudformation-cli"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.1.4"
            },
            {
              "fixed": "0.2.29"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "confidence": "high",
    "source": "matched",
    "strategy": "registry",
    "upstream_evidence": [
      {
        "ecosystem": "PyPI",
        "key": "pkg:pypi/werkzeug@3.1.8",
        "name": "werkzeug",
        "resource": "werkzeug",
        "strategy": "registry",
        "subject_version": "3.1.8"
      }
    ]
  },
  "details": "Browsers may allow \"nameless\" cookies that look like `=value` instead of `key=value`. A vulnerable browser may allow a compromised application on an adjacent subdomain to exploit this to set a cookie like `=__Host-test=bad` for another subdomain.\n\nWerkzeug \u003c= 2.2.2 will parse the cookie `=__Host-test=bad` as `__Host-test=bad`. If a Werkzeug application is running next to a vulnerable or malicious subdomain which sets such a cookie using a vulnerable browser, the Werkzeug application will see the bad cookie value but the valid cookie key.",
  "id": "BREW-cloudformation-cli-CVE-2023-23934",
  "modified": "2026-09-17T17:52:57Z",
  "published": "2026-08-13T16:40:09Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/pallets/werkzeug/security/advisories/GHSA-px8h-6qxv-m22q"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2023-23934"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pallets/werkzeug/commit/cf275f42acad1b5950c50ffe8ef58fe62cdce028"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/pallets/werkzeug"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pallets/werkzeug/releases/tag/2.2.3"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/advisory-database/tree/main/vulns/werkzeug/PYSEC-2023-57.yaml"
    },
    {
      "type": "WEB",
      "url": "https://security.netapp.com/advisory/ntap-20230818-0003"
    },
    {
      "type": "WEB",
      "url": "https://www.debian.org/security/2023/dsa-5470"
    }
  ],
  "schema_version": "1.7.3",
  "severity": [
    {
      "score": "CVSS:3.1/AV:A/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Incorrect parsing of nameless cookies leads to __Host- cookies bypass",
  "upstream": [
    "GHSA-px8h-6qxv-m22q",
    "CVE-2023-23934",
    "PYSEC-2023-57"
  ]
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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.


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.