Vulnerability · Published Jul 10, 2026 · Assigned by VulnCheck
CVE-2026-56329Capgo - Cross-Tenant Preview Namespace Collision via Non-Bijective Underscore Decoding
Medium 6.4
In plain English
A medium-severity security flaw in Capgo from Capgo. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 26% of all known vulnerabilities).
Severity (CVSS 3.1)6.4Medium
Exploit odds (30 days)0.3%top 74.3% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known
Official description
Capgo before 12.128.2 contains a cross-tenant preview namespace collision vulnerability caused by non-bijective decoding of double underscores to dots in preview hostname parsing. Attackers can register app IDs with underscores that collide with other tenants' dotted app IDs, causing preview misrouting and denial of preview access for victim applications.
Affected products (as reported)
Weakness: CWE-436 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:L