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TI-2026-20838 Aliases CVE-2026-25771

Wazuh Vulnerable to Denial of Service via Synchronous I/O Blocking in Asynchronous Authentication Middleware

Priority HIGH 72CWE-400Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-400.

Summary

Wazuh is a free and open source platform used for threat prevention, detection, and response. Starting in version 4.3.0 and prior to version 4.14.3, a Denial of Service (DoS) vulnerability exists in the Wazuh API authentication middleware (`middlewares.py`). The application uses an asynchronous event loop (Starlette/Asyncio) to call a synchronous function (`generate_keypair`) that performs blocking disk I/O on every request containing a Bearer token. An unauthenticated remote attacker can exploit this by flooding the API with requests containing invalid Bearer tokens. This forces the single-threaded event loop to pause for file read operations repeatedly, starving the application of CPU resources and potentially preventing it from accepting or processing legitimate connections. Version 4.14.3 fixes the issue.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00495 42nd percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed wazuh (wazuh): 4.14.3

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
Wazuhwazuh4.3.0 to before 4.14.34.14.3Patch availableCNA
  • wazuh VendorWazuh Affected 4.3.0 to before 4.14.3 Fixed in 4.14.3 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:wazuh:wazuh:*:*:*:*:*:*:*:*4.3.0 to before 4.14.3VulnerableWazuh
  • cpe:2.3:a:wazuh:wazuh:*:*:*:*:*:*:*:* Versions 4.3.0 to before 4.14.3 Vulnerable ·Wazuh

Remediation

  • Fix · CNA wazuh (wazuh) Fixed in 4.14.3

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-25771
  2. 2026-10-25 EPSS moved to the below the 50th percentile

References

Exploit 1

  • TI-2025-17783 Remote code execution in Wazuh server KEVCVSS 3.1CRITICAL 9.9
  • TI-2026-23722 Path traversal in wazuh CVSS 3.1CRITICAL 9.9
  • TI-2024-01157 Remote code execution and local privilege escalation in Wazuh Windows agent via NetNTLMv2 hash theft CVSS 4.0CRITICAL 9.5
  • TI-2026-22556 Wazuh: Pre-auth stack-based buffer overflow in wazuh-remoted print_hex_string() due to signed char promotion on x86_64 CVSS 3.1HIGH 8.2
  • TI-2026-35598 Wazuh: cluster peer can read arbitrary master files and forge offline REST API… CVSS 3.1CRITICAL 9.1
  • TI-2026-35467 Wazuh: merged-file header path traversal in cluster sync allows arbitrary file write under WAZUH_PATH in Wazuh manager CVSS 3.1CRITICAL 9.1
See all 72 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences