TanOS: Improper Certificate Validation
CVE-2026-121565 is a high-severity improper certificate validation vulnerability in TanOS from Tanium, with a CVSS 3.1 base score of 7.4 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 1.8.5.0326, 1.8.6.0193, 1.9.0.0089 as the first without the flaw, so updating TanOS to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.16% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update TanOS to 1.8.5.0326 or 1.8.6.0193 or 1.9.0.0089, whichever matches your release line, or a later version.
- Update Asset to 1.33.334 or 1.36.182 or 1.39.164, whichever matches your release line, or a later version.
- Update Comply to 2.32.275 or 2.35.337 or 2.37.347, whichever matches your release line, or a later version.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Tanium | TanOS | 1.8.5 up to, but not including, 1.8.5.0326; 1.8.6 up to, but not including, 1.8.6.0193; 1.9.0 up to, but not including, 1.9.0.0089 | 1.8.5.0326, 1.8.6.0193, 1.9.0.0089 |
| Tanium | Asset | 1.33 up to, but not including, 1.33.334; 1.36 up to, but not including, 1.36.182; 1.39 up to, but not including, 1.39.164 | 1.33.334, 1.36.182, 1.39.164 |
| Tanium | Comply | 2.32 up to, but not including, 2.32.275; 2.35 up to, but not including, 2.35.337; 2.37 up to, but not including, 2.37.347 | 2.32.275, 2.35.337, 2.37.347 |
| Tanium | Connect | 5.29 up to, but not including, 5.29.272; 5.37 up to, but not including, 5.37.177; 5.47 up to, but not including, 5.47.135 | 5.29.272, 5.37.177, 5.47.135 |
| Tanium | Integrity Monitor | 3.6 up to, but not including, 3.6.608; 3.7 up to, but not including, 3.7.383; 3.8 up to, but not including, 3.8.362 | 3.6.608, 3.7.383, 3.8.362 |
| Tanium | Health Check | 1.13 up to, but not including, 1.13.653 | 1.13.653 |
| Tanium | Endpoint Configuration Toolset Solution | 1.51 up to, but not including, 1.51.61; 1.59 up to, but not including, 1.59.51; 1.71 up to, but not including, 1.71.26 | 1.51.61, 1.59.51, 1.71.26 |
| Tanium | Patch | 3.24 up to, but not including, 3.24.328; 3.28 up to, but not including, 3.28.346; 3.32 up to, but not including, 3.32.383 | 3.24.328, 3.28.346, 3.32.383 |
| Tanium | Performance | 1.25 up to, but not including, 1.25.196 | 1.25.196 |
| Tanium | Reputation | 6.6 up to, but not including, 6.6.150; 6.7 up to, but not including, 6.7.143; 6.8 up to, but not including, 6.8.167 | 6.6.150, 6.7.143, 6.8.167 |
| Tanium | Reveal | 2.4 up to, but not including, 2.4.109; 2.5 up to, but not including, 2.5.166 | 2.4.109, 2.5.166 |
| Tanium | Threat Response | 4.9 up to, but not including, 4.9.480; 4.12 up to, but not including, 4.12.353; 4.17 up to, but not including, 4.17.333 | 4.9.480, 4.12.353, 4.17.333 |
| Tanium | Provision Host | 10.4.100 up to, but not including, 10.4.100; 10.8.115 up to, but not including, 10.8.115; 10.9.113 up to, but not including, 10.9.113; 10.10.189 up to, but not including, 10.10.189; 10.11.127 up to, but not including, 10.11.127 | 10.4.100, 10.8.115, 10.9.113, 10.10.189, 10.11.127 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- HighSuccess depends on conditions outside the attacker's control.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N. Scored by CNA.
Official 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.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Certificate Validation
The product does not validate, or incorrectly validates, a certificate.
How developers prevent this class of flaw
- Certificates should be carefully managed and checked to assure that data are encrypted with the intended owner's public key.
- If certificate pinning is being used, ensure that all relevant properties of the certificate are fully validated before the certificate is pinned, including the hostname.
More Improper Certificate Validation vulnerabilities (CWE-295)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other references
Recent Improper Certificate Validation vulnerabilities
- 7.4 High severity
- 7.5 High severity
- 8.0 High severity
- 8.3 High severity
- 8.7 High severity
- 8.1 High severity
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