{"id":"CVE-2026-28221","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-28221","generatedAt":"2026-10-28T09:26:03.644Z","title":"From version 4.8.0 to before version 4.14.4, a stack-based buffer overflow exists in print_hex_string() in wazuh-remoted.","description":"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 bytes such as 0xFF, the formatting can emit \"ffffffff\" (8 chars) instead of \"ff\" (2 chars), causing an out-of-bounds write past a fixed 2049-byte stack buffer. The vulnerable path is reachable remotely prior to any agent authentication/registration logic via TCP/1514 when an oversized length prefix causes the “unexpected message (hex)” diagnostic path to run. Additionally, the same unauthenticated oversized-message diagnostic path logs an attacker-controlled hex dump to /var/ossec/logs/ossec.log for each trigger, allowing remote log amplification that can degrade monitoring fidelity and consume disk/I/O. This log amplification is reachable even without triggering the sign-extension overflow (e.g., using bytes < 0x80). This issue has been patched in version 4.14.4.","published":"2026-04-29T19:16:23.000Z","lastModified":"2026-06-17T10:28:21.000Z","status":"Analyzed","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"3.1","score":8.2,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H"},"cwe":["CWE-121","CWE-400"],"affected":["wazuh/wazuh"],"epss":{"score":0.00382,"percentile":0.32051,"date":"2026-10-27","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.38%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://github.com/wazuh/wazuh/releases/tag/v4.14.4","tags":["Release Notes"],"source":"security-advisories@github.com"},{"url":"https://github.com/wazuh/wazuh/security/advisories/GHSA-q9vv-7w4c-f4cm","tags":["Exploit","Vendor Advisory"],"source":"security-advisories@github.com"},{"url":"https://github.com/wazuh/wazuh/security/advisories/GHSA-q9vv-7w4c-f4cm","tags":["Exploit","Vendor Advisory"],"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-28221","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}