CVE-2026-56316 json
Cap-go - Job Existence Oracle via Unauthenticated OPTIONS /build/upload/:jobId/*
published 4mo ago modified 3d ago also EUVD-2026-38172
- cvss
- 5.3
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 24%
- public exploits
- 0
- none known
Summary
Cap-go before 12.128.2 contains an information disclosure vulnerability in the OPTIONS /build/upload/:jobId/* endpoint that allows unauthenticated attackers to enumerate valid builder job IDs through observable response discrepancies. Attackers can probe the endpoint without authentication to distinguish valid job IDs from invalid ones and generate sustained unauthenticated traffic for resource consumption.
Patch / fix
- Cap-go capgo 12.128.2
Is CVE-2026-56316 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.
Check with FencerCISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 4mo ago
Exploit prediction
0.31% chance of exploitation in the next 30 days, higher than 24% of all scored CVEs (FIRST EPSS, 2026-11-11).
Exploits and checks
- github.com https://github.com/Cap-go/capgo/security/advisories/GHSA-9c2x-7h5x-37gm referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 6.9 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N |
| CNA | 3.1 | 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N |
| CNA | 4.0 | 6.9 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/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 |
Affected products
- Cap-go capgo
Classification
- Weakness
-
- CWE-203 Observable Discrepancy
References
-
github.com
/Cap-go/capgo/security/advisories/GHSA-9c2x-7h5x-37gm
vendor-advisory, exploit
-
vulncheck.com
/advisories/cap-go-job-existence-oracle-via-unauthenticated-options-build-upload-jobid
third-party-advisory
Sources
- CVE List CVE-2026-56316
- NVD CVE-2026-56316
Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.