CVE-2026-56233
HIGH 8.7Capgo before 12.128.2 contains a path traversal vulnerability in the builder upload proxy that allows authenticated users with build permissions to bypass upload restrictions. Attackers can append traversal sequences to the upload path, which are normalized by the WHATWG URL parser, enabling access to internal administrative endpoints with the privileged BUILDER_API_KEY header and resulting in server-side privilege escalation.
ELEVATED IMPACT
Severe if exploited (CVSS 8.7), but no known exploitation and low modeled probability. Patch on a normal cadence.
Exploitation likelihood
0.5%chance of exploitation in 30 days · 36th percentile
○ In CISA KEV
○ Public exploit / PoC
Impact if exploited
8.7CVSS 4.0 · HIGH
- ConfidentialityHigh
- IntegrityHigh
- AvailabilityLow
What an attacker needs
- ✓Access: Reachable over the network — no local access needed
- ⚠Privileges: Requires a low-privilege account
- ✓User interaction: No user interaction needed
- ✓Complexity: No special conditions — reliably repeatable
- ✓Requirements: No special attack requirements
✓ lowers the bar for an attacker · ⚠ raises it
Weakness (CWE)
- CWE-22: Path traversal
CVSS vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N