Medium 6.4Published Jul 10, 2026

CVE-2026-56329Capgo - Cross-Tenant Preview Namespace Collision via Non-Bijective Underscore Decoding

Updated under an hour ago (Oct 28, 2026, 3:30 AM ET)

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No exploitation reported and no EPSS estimate yet.

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Every CVE for Capgo

Exploited in the last 30 days

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.

CVSS: 6.4 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:L
Weakness (CWE): CWE-436
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: VulnCheck
NVD analysis: Deferred
Record last updated: Jul 10, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Capgo Capgo capgo:capgo (from the name)	before 12.128.2; 12.128.2 not affected	CNA record

References

References

https://github.com/Cap-go/capgo/security/advisories/GHSA-76qq-gg2p-pwwj	vendor-advisory
https://www.vulncheck.com/advisories/capgo-cross-tenant-preview-namespace-collision-via-non-bijective-underscore-decoding	third-party-advisory

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.