CVE-2021-29480

Default client side session signing key is highly predictable

LOW
3.1
CVSS Score
Published: June 29, 2021 at 06:15 PM UTC
Updated: June 17, 2026 at 03:47 AM UTC
1 product affected across 1 vendorProject Ratpack

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Severity
LOW3.1
Exploit prediction
EPSS 0.3%

Description

Ratpack is a toolkit for creating web applications. In versions prior to 1.9.0, the client side session module uses the application startup time as the signing key by default. This means that if an attacker can determine this time, and if encryption is not also used (which is recommended, but is not on by default), the session data could be tampered with by someone with the ability to write cookies. The default configuration is unsuitable for production use as an application restart renders all sessions invalid and is not multi-host compatible, but its use is not actively prevented. As of Ratpack 1.9.0, the default value is a securely randomly generated value, generated at application startup time. As a workaround, supply an alternative signing key, as per the documentation's recommendation.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 1.9.0
Affected range stops below 1.9.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

CVSS

Attack Vector
NETWORK
Complexity
HIGH
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-340CWE-330

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