Vulnerability · Published Sep 26, 2026 · Assigned by VulnCheck

CVE-2026-100625Capgo Build Upload Proxy Authorization Bypass via TUS Resource

High 7.1

In plain English

A high-severity security flaw in capgo.app from Cap-go. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 23% of all known vulnerabilities).

Severity (CVSS 3.1)7.1High

Exploit odds (30 days)0.3%top 77.2% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

Capgo (capgo.app) exposes a native build TUS upload proxy (supabase/functions/_backend/public/build/upload.ts) that authorizes a caller against a single build job identified by the supplied builder_job_id and validates only that job's stored upload_path, but then forwards the user-controlled TUS resource suffix taken from /build/upload/:jobId/* to the builder service while injecting Capgo's privileged builder API key. Because the forwarded suffix is never bound to the authorized job's upload_path or upload_session_key, a caller holding a valid 'all' or 'write' Capgo API key with app.build_native permission for one application can use its authorized proxy path for job A to write to the TUS upload resource of another job B, provided that resource suffix is known or exposed, corrupting that build's artifacts. All versions are affected; no patch was available at the time of advisory publication.

Affected products (as reported)

Vendor	Product	Versions
Cap-go	capgo.app	0 – through *

Weakness: CWE-441 · Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:N/I:H/A:L

References

GitHub Security Advisory (GHSA-r45q-x4gr-3mvv) vendor-advisory
VulnCheck Advisory: Capgo Build Upload Proxy Authorization Bypass via TUS Resource third-party-advisory