CVE-2026-56299
Capgo - Denial of Service via Unauthenticated OPTIONS Request to /build/upload Endpoint
Capgo before 12.128.2 contains an authentication bypass vulnerability in the /build/upload/:jobId/* endpoint that allows unauthenticated attackers to trigger consistent 500 errors. Remote attackers can send OPTIONS requests to bypass authentication middleware and invoke tusProxy logic with invalid credentials, enabling trivial request flooding and denial of service.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- Low
Exploit likelihood
What each source reports
CVE List Score used
Capgo - Denial of Service via Unauthenticated OPTIONS Request to /build/upload Endpoint
Capgo before 12.128.2 contains an authentication bypass vulnerability in the /build/upload/:jobId/* endpoint that allows unauthenticated attackers to trigger consistent 500 errors. Remote attackers can send OPTIONS requests to bypass authentication middleware and invoke tusProxy logic with invalid credentials, enabling trivial request flooding and denial of service.
- Record
CVE-2026-56299- CVSS 4.0
- 6.9 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N - CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L - Weakness
- CWE-306
- Updated
- 2026-11-08
EUVDEUVD-2026-38171
Capgo before 12.128.2 contains an authentication bypass vulnerability in the /build/upload/:jobId/* endpoint that allows unauthenticated attackers to trigger consistent 500 errors. Remote attackers can send OPTIONS requests to bypass authentication middleware and invoke tusProxy logic with invalid credentials, enabling trivial request flooding and denial of service.
- Record
EUVD-2026-38171- CVSS 4.0
- 6.9 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N - Updated
- 2026-11-08
GitHub AdvisoriesGHSA-33r3-cpxm-4xg2
Capgo before 12.128.2 contains an authentication bypass vulnerability in the /build/upload/:jobId...
Capgo before 12.128.2 contains an authentication bypass vulnerability in the /build/upload/:jobId/* endpoint that allows unauthenticated attackers to trigger consistent 500 errors. Remote attackers can send OPTIONS requests to bypass authentication middleware and invoke tusProxy logic with invalid credentials, enabling trivial request flooding and denial of service.
- Record
GHSA-33r3-cpxm-4xg2- CVSS 4.0
- 6.9 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/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 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L - Weakness
- CWE-306
- Updated
- 2026-11-02
NVD
Capgo before 12.128.2 contains an authentication bypass vulnerability in the /build/upload/:jobId/* endpoint that allows unauthenticated attackers to trigger consistent 500 errors. Remote attackers can send OPTIONS requests to bypass authentication middleware and invoke tusProxy logic with invalid credentials, enabling trivial request flooding and denial of service.
- Record
CVE-2026-56299- CVSS 4.0
- 6.9 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/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 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L - Weakness
- CWE-306
- Updated
- 2026-11-02
OSV
Capgo - Denial of Service via Unauthenticated OPTIONS Request to /build/upload Endpoint
Capgo before 12.128.2 contains an authentication bypass vulnerability in the /build/upload/:jobId/* endpoint that allows unauthenticated attackers to trigger consistent 500 errors. Remote attackers can send OPTIONS requests to bypass authentication middleware and invoke tusProxy logic with invalid credentials, enabling trivial request flooding and denial of service.
- Record
CVE-2026-56299- CVSS 4.0
- 6.9 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N - Weakness
- CWE-306
- Updated
- 2026-11-09
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| facts | EUVD | |
| aliases, products, published | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-56299 is a medium vulnerability (CVSS 6.9) in Cap-go Capgo, published June 21, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.68%, the 52nd percentile. No source names a fixed version.
References
github.com/Cap-go/capgo/security/advisories/GHSA-6c7m-4223-446j
vulncheck.com/advisories/capgo-denial-of-service-via-unauthenticated-options-request-to-build-upload-endpoint
nvd.nist.gov/vuln/detail/CVE-2026-56299