CVE-2021-29485Network attack vector

Remote code execution via unsafe session deserialization

Published Jun 29, 2021 · Updated Aug 3, 2024

Insecure deserialization in Ratpack before 1.9.0 allows remote authenticated users to execute arbitrary code through session data. SessionSerializer accepts arbitrary object types, and a trusted outer type can cause nested unsafe gadget types to be deserialized without a strict allowlist. Exploitation requires Ratpack sessions plus write access to server-side session storage or the secrets protecting client-side session cookies.

CVSS severity9.9
Critical
EPSS probability1.99%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Insecure deserialization in Ratpack before 1.9.0 allows remote authenticated users to execute arbitrary code through session data. SessionSerializer accepts arbitrary object types, and a trusted outer type can cause nested unsafe gadget types to be deserialized without a strict allowlist. Exploitation requires Ratpack sessions plus write access to server-side session storage or the secrets protecting client-side session cookies.

The record

CVE
CVE-2021-29485
Published
Jun 29, 2021
Updated
Aug 3, 2024
Vendor
Ratpack
Product
Ratpack
Classifications
CWE-502, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 29, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.9.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Ratpack · Ratpackversion=< 1.9.0

Published CVSS scores

6.5NVDAV:N/AC:L/Au:S/C:P/I:P/A:P
9.9GitHubCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
8.8NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-502Deserialization of Untrusted Data
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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