CVE-2026-44255 — Wazuh: Username Enumeration via Timing Side-Channel
Wazuh is a free and open source platform used for threat prevention, detection, and response. From 4.0.0 until 4.14.6 and 5.0.0-beta2, AuthenticationManager.check_user() in framework/wazuh/rbac/orm.py performs check_password_hash() only when the supplied username exists. A nonexistent username returns immediately, while a valid username causes an expensive bcrypt calculation. An unauthenticated remote attacker can compare authentication response times to enumerate valid Wazuh usernames and use that information in subsequent credential attacks. This issue is fixed in versions 4.14.6 and 5.0.0-beta2.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- Technical severity (medium)+3
- Automatable exploitation (SSVC)+3
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
CISA SSVC assessment CISA
Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
- Documented patch — github.com (NIST National Vulnerability Database)
- Documented patch — github.com (NIST National Vulnerability Database)
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Wazuh Wazuh).
- The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
- Apply the fixed version or the patch documented under Remediation.
- Search available logs for exploit probes, errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 5.3 | CVSS 3.1 | Medium | 3.9 | 1.4 | security-advisories@github.com via NIST National Vulnerability Database |
| 5.3 | CVSS 3.1 | Medium | — | — | GitHub_M via CVE Program (cve.org) e CISA ADP |
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N (score shown at the top: security-advisories@github.com) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products added · wazuh/wazuh
- SSVC assessment updated
- Record published
- Fix documented
- CVSS changed · 5.3
- Source status changed · → Analyzed
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× Official description updated · Oct 15, 2026 – Oct 15, 2026
References
5 on the record
Elsewhere on this site
Related CVEs (same products)
- High CVE-2026-71540 Wazuh Manager cluster header parsing allows pre-authentication memory exhaustion 21d
- Medium CVE-2026-61811 Wazuh: Unbounded Recursion in os_xml `_getattributes()` Causes analysisd Worker Thread Stack Exhaustion 21d
- Critical CVE-2026-61800 Path Traversal in Wazuh Aug 27, 2026
- Medium CVE-2026-61802 Wazuh discloses cleartext cluster key to low-privilege API users via GET /cluster/local/config Aug 27, 2026
- High CVE-2026-54085 Wazuh: Missing input validation in multiple active response scripts allows argument injection Aug 27, 2026
- Medium CVE-2026-54084 Wazuh agent enrollment NULL pointer dereference via malformed manager response Aug 27, 2026
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No FIRST EPSS score.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2026-44255 is "Wazuh: Username Enumeration via Timing Side-Channel", rated Medium. It affects Wazuh (Wazuh); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 5.3 describes technical severity. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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