CVE-2026-28221: Wazuh is a free and open source platform used for threat prevention, detection, and response

This week

MEDIUM 6.5REMOTEUPGRADE

CVE-2026-28221 is a medium-severity flaw (CVSS 6.5) affecting wazuh. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Wazuh is a free and open source platform used for threat prevention, detection, and response. From version 4.8.0 to before version 4.14.4, a stack-based buffer overflow exists in print_hex_string() in wazuh-remoted. The bug is triggered when formatting attacker-controlled bytes using sprintf(dst_buf + 2*i, "%.2x", src_buf[i]) on platforms where char is treated as signed and the compiled code sign-extends bytes before the variadic call. For input

Why this priority

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

A fixed release or distro patch exists.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.4% (top 68%)
CISA exploited list	No
Weakness	CWE-121, CWE-400
Published	2026-04-29
Last modified	2026-06-17

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

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

Am I affected?

Timeline

2026-04-29 19:16 UTCPublished CVE record published
2026-06-17 10:28 UTCUpdated Record last modified

wazuh wazuh UPGRADE

Affected: >= 4.8.0 and < 4.14.4

Fixed in: 4.14.4

Safe to downgrade to: a release before 4.8.0

1. Check installed version

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

2. UPGRADE to 4.14.4 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade wazuh

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 4.8.0 (Debian / Ubuntu)

apt-cache madison wazuh sudo apt install wazuh=<VERSION_BEFORE_4.8.0> sudo apt-mark hold wazuh

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

dnf --showduplicates list wazuh sudo dnf downgrade wazuh-<VERSION_BEFORE_4.8.0> sudo dnf versionlock add wazuh

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-2026-28221?

wazuh: upgrade to 4.14.4. Exact commands for each OS are on this page.

Is CVE-2026-28221 being exploited?

CVE-2026-28221 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-2026-28221 affect?

CVE-2026-28221 affects wazuh. Severity is medium (CVSS 6.5). Wazuh is a free and open source platform used for threat prevention, detection, and response. From version 4.8.0 to before version 4.14.4, a stack-based buffer overflow exists in print_hex_string() in wazuh-remoted. The bug is triggered whe

How urgent is CVE-2026-28221?

Priority 41/100. Public exploit reference; Remotely exploitable, no login, no user action

Software pages

Wazuh vulnerabilities

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References

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