CVE-2019-11808: Ratpack versions before 1.6.1 generate a session ID using a cryptographically weak PRNG in the JDK's ThreadLoc

Q: How do I fix CVE-2019-11808?

ratpack: upgrade to 1.6.1. Exact commands for each OS are on this page.

Q: Is CVE-2019-11808 being exploited?

CVE-2019-11808 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2019-11808 affect?

CVE-2019-11808 affects ratpack. Severity is low (CVSS 3.7). Ratpack versions before 1.6.1 generate a session ID using a cryptographically weak PRNG in the JDK's ThreadLocalRandom. This means that if an attacker can determine a small window for the server start time and obtain a session ID value, the

Q: How urgent is CVE-2019-11808?

Priority 36/100. Remotely exploitable, no login, no user action

Routine

LOW 3.7REMOTEUPGRADE

CVE-2019-11808 is a low-severity flaw (CVSS 3.7) affecting ratpack. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Ratpack versions before 1.6.1 generate a session ID using a cryptographically weak PRNG in the JDK's ThreadLocalRandom. This means that if an attacker can determine a small window for the server start time and obtain a session ID value, they can theoretically determine the sequence of session IDs.

Why this priority

Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	3.7 (Low)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	1.3% (top 29%)
CISA exploited list	No
Weakness	CWE-338
Published	2019-05-07
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: ratpack project

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2019-05-07 07:29 UTCPublished CVE record published
2026-06-17 02:13 UTCUpdated Record last modified

ratpack project ratpack UPGRADE

Affected: < 1.6.1

Fixed in: 1.6.1

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy ratpack || rpm -q ratpack || ratpack --version

2. UPGRADE to 1.6.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade ratpack

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade ratpack

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2019-11808?

ratpack: upgrade to 1.6.1. Exact commands for each OS are on this page.

Is CVE-2019-11808 being exploited?

CVE-2019-11808 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2019-11808 affect?

CVE-2019-11808 affects ratpack. Severity is low (CVSS 3.7). Ratpack versions before 1.6.1 generate a session ID using a cryptographically weak PRNG in the JDK's ThreadLocalRandom. This means that if an attacker can determine a small window for the server start time and obtain a session ID value, the

How urgent is CVE-2019-11808?

Priority 36/100. Remotely exploitable, no login, no user action

Related CVEs

CVE-2021-29485 CRITICAL 9.9 UPGRADE Ratpack is a toolkit for creating web applications
CVE-2021-29481 MEDIUM 6.5 UPGRADE Ratpack is a toolkit for creating web applications
CVE-2021-29480 MEDIUM 4.4 UPGRADE Ratpack is a toolkit for creating web applications
CVE-2021-29479 HIGH 7.0 UPGRADE Ratpack is a toolkit for creating web applications
CVE-2019-17513 HIGH 7.5 UPGRADE An issue was discovered in Ratpack before 1.7.5

References

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