Security advisory
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
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"
}