Resource exhaustion in Capgo
CVE-2026-56309
Capgo before 12.128.2 fails to enforce plan/quota restrictions on the /files/upload/attachments endpoint, allowing plan-blocked apps to create publicly readable R2 objects. Attackers can upload arbitrary attachments using upload-scoped API keys that bypass plan checks, persist outside normal bundle metadata, and survive app deletion, enabling storage and bandwidth abuse.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L.
EPSS exploit prediction
EPSS: 0.004 (27.2th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 27th percentile — 27.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000
Affected products
- Capgo — versions 0, 12.128.2
Weakness classification (CWE)
References
- github.com/Cap-go/capgo/security/advisories/GHSA-q52j-ggvx-cr4v (vendor-advisory)
- www.vulncheck.com/advisories/capgo-plan-bypass-via-unrestricted-attachment-uplo… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-56309?
- CVE-2026-56309 is a medium-severity vulnerability in Capgo, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 5.4/10. Published 2026-07-10.
- How severe is CVE-2026-56309?
- Medium severity. CVSS v3 base score is 5.4 out of 10.