CVE-2026-56329 Capgo - Cross-Tenant Preview Namespace Collision via Non-Bijective Underscore Decoding
Attackers can cause cross-tenant preview misrouting and denial of service by exploiting non-bijective underscore decoding in Capgo's hostname parsing.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-56329?
CVE-2026-56329 is a medium-severity vulnerability in Capgo, published on 10 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.
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.
Weakness: CWE-436
Which versions are affected by CVE-2026-56329?
How do I fix CVE-2026-56329?
No fix has been published for CVE-2026-56329 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-56329 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-56329 exists.
Sources
Also known as GHSA-42q8-ww2w-fgmm, GHSA-76qq-gg2p-pwwj.