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Security advisory

Type: advisorySources: OSVCVE: CVE-2021-29485

Ratpack is a toolkit for creating web applications. In versions prior to 1.9.0, a malicious attacker can achieve Remote Code Execution (RCE) via a maliciously crafted Java deserialization gadget chain leveraged against the Ratpack session store. If one's application does not use Ratpack's session mechanism, it is not vulnerable. Ratpack 1.9.0 introduces a strict allow-list mechanism that mitigates this vulnerability when used. Two possible workarounds exist. The simplest mitigation for users of earlier versions is to reduce the likelihood of attackers being able to write to the session data store. Alternatively or additionally, the allow-list mechanism could be manually back ported by providing an alternative implementation of `SessionSerializer` that uses an allow-list.

Products
Not specified
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2021-29485
Confirmed fixed CVEs
Not specified
Updated in this feed
31 Oct 2026, 11:44 UTC · Revision 1

Source evidence

CVE-2021-29485

core-osv · Original source

Published 29 Jun 2021, 19:15 UTC

Ratpack is a toolkit for creating web applications. In versions prior to 1.9.0, a malicious attacker can achieve Remote Code Execution (RCE) via a maliciously crafted Java deserialization gadget chain leveraged against the Ratpack session store. If one's application does not use Ratpack's session mechanism, it is not vulnerable. Ratpack 1.9.0 introduces a strict allow-list mechanism that mitigates this vulnerability when used. Two possible workarounds exist. The simplest mitigation for users of earlier versions is to reduce the likelihood of attackers being able to write to the session data store. Alternatively or additionally, the allow-list mechanism could be manually back ported by providing an alternative implementation of `SessionSerializer` that uses an allow-list.

osv:CVE-2021-29485
Complete source record
{
  "id": "a7219068d3303ef89d5a576c382f32396297a7b71632bbdc9fab1dd271b099b5",
  "url": "https://osv.dev/vulnerability/CVE-2021-29485",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2021-29485",
    "summary": "Ratpack is a toolkit for creating web applications. In versions prior to 1.9.0, a malicious attacker can achieve Remote Code Execution (RCE) via a maliciously crafted Java deserialization gadget chain leveraged against the Ratpack session store. If one's application does not use Ratpack's session mechanism, it is not vulnerable. Ratpack 1.9.0 introduces a strict allow-list mechanism that mitigates this vulnerability when used. Two possible workarounds exist. The simplest mitigation for users of earlier versions is to reduce the likelihood of attackers being able to write to the session data store. Alternatively or additionally, the allow-list mechanism could be manually back ported by providing an alternative implementation of `SessionSerializer` that uses an allow-list.",
    "evidence": "osv:CVE-2021-29485",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2021-29485",
      "aliases": [
        "CVE-2021-29485",
        "GHSA-hc33-32vw-rpp9"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/ratpack/ratpack",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "d62e05d331577684670e793d9273bb3ddb4c7f6e"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:ratpack_project:ratpack:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "1.9.0"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v1.9.0-rc-2",
            "v1.9.0-rc-1",
            "v1.8.2",
            "v1.8.1",
            "v1.8.0",
            "v1.7.3",
            "v1.7.2",
            "v1.7.1",
            "v1.7.0",
            "v1.6.0",
            "v1.6.0-rc-4",
            "v1.6.0-rc-3",
            "v1.6.0-rc-2",
            "1.6.0-rc-1",
            "v1.5.0",
            "v1.5.0-rc-3",
            "v1.5.0-rc-1",
            "v1.4.0",
            "v1.4.0-rc-3",
            "v1.4.0-rc-2",
            "v1.4.0-rc-1",
            "v1.3.1",
            "v1.3.0",
            "v1.3.0-rc-2",
            "v1.3.0-rc-1",
            "v1.2.0",
            "v1.2.0-rc-2",
            "v1.2.0-RC-1",
            "v1.1.1",
            "v1.1.0",
            "v1.0.0",
            "v1.0.0-rc-3",
            "v1.0.0-rc-2",
            "v1.0.0-rc-1",
            "v0.9.19",
            "v0.9.18",
            "v0.9.17",
            "v0.9.16",
            "v0.9.15",
            "v0.9.14",
            "v0.9.13",
            "v0.9.12",
            "v0.9.11",
            "v0.9.10",
            "v0.9.9",
            "v0.9.8",
            "v0.9.7",
            "v0.9.6",
            "v0.9.5",
            "v0.9.4",
            "v0.9.3",
            "v0.9.2",
            "v0.9.1",
            "v0.9.0",
            "0.6.1",
            "0.5.2"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-29485.json"
          }
        }
      ],
      "modified": "2026-10-20T10:54:37.397795583Z",
      "provider": "osv",
      "references": [
        "https://github.com/ratpack/ratpack/security/advisories/GHSA-hc33-32vw-rpp9",
        "https://mvnrepository.com/artifact/io.ratpack/ratpack-core"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2021-29485",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 385768,
  "published_at": "2021-06-29T19:15:09.607+00:00"
}