Unencrypted storage of client side sessions

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

6.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

EPSS

• CVE-2021-29481: 0.46% estimated exploitation activity in the next 30 days; percentile 39.57 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact The default configuration of client side sessions results in unencrypted, but signed, data being set as cookie values. This means that if something sensitive goes into the session, it could be read by something with access to the cookies. Note: the documentation does point this out and encourage users to add an encryption key, but it is not mandatory. For this to be a vulnerability, some kind of sensitive data would need to be stored in the session and the session cookie would have to leak. For example, the cookies are not configured with httpOnly and an adjacent XSS vulnerability within the site allowed capture of the cookies. The proposed change is to change the default behaviour to use a randomly generated encryption key. This would mean that sessions do not survive app restarts, but this is already the behaviour given the random signing key. Patches As of version 1.9.0, a securely randomly generated signing key is used. Workarounds Supply an encryption key, as per the…

Published by the source

1 Jul 2021, 17:02 UTC

Last modified by the source

1 Feb 2023, 05:06 UTC

Source last checked

26 Oct 2026, 16:07 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-phj8-4cq3-794g

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# Patch Next advisory brief: CVE-2021-29481

Advisory: Unencrypted storage of client side sessions
IDs: CVE-2021-29481, GHSA-phj8-4cq3-794g
Record: https://patchnext.com/advisories/cve-2021-29481 (revision 1, source checked 26 Oct 2026, 16:07 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: io.ratpack:ratpack-session 1.9.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven io.ratpack:ratpack-session: affected < 1.9.0; fixed in 1.9.0

## Suggested inspection (read-only)
- Maven io.ratpack:ratpack-session: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on io.ratpack:ratpack-session.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-phj8-4cq3-794g (GitHub-reviewed advisory GHSA-phj8-4cq3-794g lists affected ranges: Maven io.ratpack:ratpack-session >=0 <1.9.0)

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