Vulnerability · Published Jun 21, 2026 · Assigned by VulnCheck

CVE-2026-56316Cap-go - Job Existence Oracle via Unauthenticated OPTIONS /build/upload/:jobId/*

Medium 5.3

In plain English

A medium-severity security flaw in capgo 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 24% of all known vulnerabilities).

Severity (CVSS 3.1)5.3Medium

Exploit odds (30 days)0.3%top 75.9% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

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.

Affected products (as reported)

Vendor	Product	Versions
Cap-go	capgo	0 – before 12.128.2

Weakness: CWE-203 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

References

GHSA Advisory GHSA-9c2x-7h5x-37gm vendor-advisory
VulnCheck Advisory: Cap-go - Job Existence Oracle via Unauthenticated OPTIONS /build/upload/:jobId/* third-party-advisory