Capgo Build Upload Proxy Authorization Bypass via TUS Resource

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-100625
StatePUBLISHED
AssignerVulnCheck
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-26 14:16:43 UTC
Updated2026-09-26 14:16:43 UTC
DescriptionCapgo (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.

Risk And Classification

Primary CVSS: v4.0 8.7 HIGH from [email protected]

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Problem Types: CWE-441 | CWE-441 Unintended Proxy or Intermediary ('Confused Deputy')

VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary8.7HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/C...
4.0CNACVSS8.7HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
3.1[email protected]Primary7.1HIGHCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:N/I:H/A:L
3.1CNACVSS7.1HIGHCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:N/I:H/A:L

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
None
User Interaction
None
Confidentiality
High
Integrity
None
Availability
None
Sub Conf.
None
Sub Integrity
None
Sub Availability
None

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
None
Integrity
High
Availability
Low

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:N/I:H/A:L

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Cap-go Capgo.app Not specified Not specified

References

ReferenceSourceLinkTags
www.vulncheck.com/advisories/capgo-build-upload-proxy-authorization-bypass-via-... [email protected] www.vulncheck.com
github.com/Cap-go/capgo.app/security/advisories/GHSA-r45q-x4gr-3mvv [email protected] github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Judel777 (en)

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