What is CVE-2026-66063?
goshs is a feature-rich single-binary file server for red teamers and developers. Prior to 2.1.5, the httpserver/updown.go multipart upload handler split part.FileName() on / but did not reject .., allowing an unauthenticated upload with filename .. to create a file outside the served tree. This issue is fixed in version 2.1.5.
The record classifies CVE-2026-66063 under weakness class CWE-22. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 69 days ago.
Severity and exploitation probability
- CVSS v3.1 base score
- 6.5 — MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N - CISA KEV
- Not listed in the CISA Known Exploited Vulnerabilities catalog
- Threadlinqs priority
- 3.3/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- Published
- 2026-07-28
Is CVE-2026-66063 being exploited?
It currently carries a trending score of 30 in the Threadlinqs vulnerability feed.
Affected products and versions
- goshs-labs: goshs
How to fix CVE-2026-66063
No vendor patch reference has been recorded for CVE-2026-66063 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.
Threat activity tracking CVE-2026-66063
No threat campaign in the Threadlinqs corpus currently references CVE-2026-66063, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.
Sources
Enriched from CVE.org, NVD. Last verified by Threadlinqs on . This product uses the NVD API but is not endorsed or certified by the NVD.