CVE-2026-28221Public exploitNetwork attack vector

Pre-auth memory corruption via signed byte formatting

Published Apr 29, 2026 · Updated Apr 29, 2026

Stack-based buffer overflow in Wazuh 4.8.0 through 4.14.3 allows remote attackers to corrupt wazuh-remoted memory via TCP/1514. In print_hex_string(), sprintf formats signed attacker-controlled bytes as up to eight hexadecimal characters while advancing a 2049-byte stack buffer by only two bytes per input byte. An oversized pre-authentication message reaches this diagnostic path; repeated triggers also append attacker-controlled hex dumps to ossec.log, consuming disk and I/O without a demonstrated reliable crash or control-flow hijack.

CVSS severity6.5
Medium
EPSS probability0.38%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack-based buffer overflow in Wazuh 4.8.0 through 4.14.3 allows remote attackers to corrupt wazuh-remoted memory via TCP/1514. In print_hex_string(), sprintf formats signed attacker-controlled bytes as up to eight hexadecimal characters while advancing a 2049-byte stack buffer by only two bytes per input byte. An oversized pre-authentication message reaches this diagnostic path; repeated triggers also append attacker-controlled hex dumps to ossec.log, consuming disk and I/O without a demonstrated reliable crash or control-flow hijack.

The record

CVE
CVE-2026-28221
Published
Apr 29, 2026
Updated
Apr 29, 2026
Vendor
Wazuh
Product
Wazuh
Classifications
CWE-400, CWE-121, T1190, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 29, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 29, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 4.8.0, < 4.14.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Wazuh · Wazuhversion=>= 4.8.0, < 4.14.4

Published CVSS scores

6.5GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
8.2NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-400Uncontrolled Resource Consumption
CWE-121Stack-based Buffer Overflow
T1190Exploit Public-Facing Application
T1499.004Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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