CVE-2026-50559: Quarkus is a Java framework for building cloud-native applications

This week

HIGH 7.5REMOTEUPGRADE

CVE-2026-50559 is a high-severity flaw (CVSS 7.5) affecting quarkus. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Quarkus is a Java framework for building cloud-native applications. Prior to versions 3.37.0, 3.36.3, 3.33.2.1, 3.33.3, 3.27.4.1, 3.27.5, and 3.20.6.2, Quarkus HTTP path-based authorization policies can be bypassed using encoded semicolons (%3B) to smuggle matrix parameters past the security layer, and using encoded slashes (%2F) or backslashes (%5C) to access protected static resources. This is a distinct issue from CVE-2026-39852, which address

Why this priority

High severity
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.0% (top 37%)
CISA exploited list	No
Weakness	CWE-287, CWE-863, CWE-551
Published	2026-06-19
Last modified	2026-10-25

Publisher (CNA): GitHub, Inc. · Vendor: quarkus

Last updated 2026-10-25 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-06-19 21:17 UTCPublished CVE record published
2026-10-25 23:10 UTCUpdated Record last modified

quarkus quarkus UPGRADE

Affected: < 3.20.6.2 · >= 3.21.0 and < 3.27.4.1 · >= 3.28.0 and < 3.33.2.1 · >= 3.34.0 and < 3.36.3

Fixed in: 3.20.6.2, 3.27.4.1, 3.33.2.1, 3.36.3

Safe to downgrade to: a release before 3.21.0

1. Check installed version

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

2. UPGRADE to 3.20.6.2 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade quarkus

Note

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

3. If no update is available yet, DOWNGRADE to a release before 3.21.0 (Debian / Ubuntu)

apt-cache madison quarkus sudo apt install quarkus=<VERSION_BEFORE_3.21.0> sudo apt-mark hold quarkus

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list quarkus sudo dnf downgrade quarkus-<VERSION_BEFORE_3.21.0> sudo dnf versionlock add quarkus

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

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-2026-50559?

quarkus: upgrade to 3.20.6.2, 3.27.4.1, 3.33.2.1, 3.36.3. Exact commands for each OS are on this page.

Is CVE-2026-50559 being exploited?

CVE-2026-50559 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-2026-50559 affect?

CVE-2026-50559 affects quarkus. Severity is high (CVSS 7.5). Quarkus is a Java framework for building cloud-native applications. Prior to versions 3.37.0, 3.36.3, 3.33.2.1, 3.33.3, 3.27.4.1, 3.27.5, and 3.20.6.2, Quarkus HTTP path-based authorization policies can be bypassed using encoded semicolons

How urgent is CVE-2026-50559?

Priority 52/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

Software pages

Java vulnerabilities

References

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