7.5High
CVE-2026-86538
knowns versions before 0.30.0 contain a path traversal vulnerability in the POST /api/templates/preview endpoint that allows unauthenticated attackers to read arbitrary files. Attackers can supply directory traversal sequences in the templateFile parameter to bypass path restrictions and read sensitive files like credentials and configuration through the JSON response.
What this means for your business
- An attacker can use it remotely, over a network, without a login, and without anyone at your company clicking anything.
- FIRST's prediction model gives it a 0.7% chance of attack attempts being seen in the next 30 days, ranking above 52% of all known flaws.
What to do
- 1Ask your IT team or provider whether any of your systems use the affected product.
- 2If you do, follow the vendor's guidance. No patch reference has been published yet.
Not sure if your company is exposed?
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Scoring
- CVSS
- 7.5 (v3.1)
- Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N- CVSS v4
- 8.7
- Weakness
- CWE-22
- Assigned by
- disclosure@vulncheck.com
Dates
- Published
- 2026-09-07
- Last modified
- 2026-09-14
- Sources
- NVD
References
- https://github.com/knowns-dev/knowns/blob/v0.29.1/internal/server/routes/templates.go#L299-L310
- https://github.com/knowns-dev/knowns/commit/09c5a96fd5817b941dc86669278c1a17db10ed4e
- https://github.com/knowns-dev/knowns/releases/tag/v0.30.0
- https://github.com/knowns-dev/knowns/security/advisories/GHSA-fpxv-c555-rhm3
- https://www.vulncheck.com/advisories/knowns-before-0.30.0-path-traversal-via-templatefile-parameter