CVE-2026-56309 json
Capgo - Plan Bypass via Unrestricted Attachment Upload Endpoint
published 2026-07-10 4 mo ago modified 2026-10-25 15 d ago also EUVD-2026-42883
- cvss
- 5.4
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 24%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- Capgo Capgo 12.128.2
CISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- no
- Technical impact
- partial
- Assessed
- 4 mo ago
Exploit prediction
0.31% chance of exploitation in the next 30 days, higher than 24% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- github.com https://github.com/Cap-go/capgo/security/advisories/GHSA-q52j-ggvx-cr4v referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 5.3 | CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N |
| CNA | 3.1 | 5.4 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L |
| CNA | 4.0 | 5.3 | CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
Affected products
- Capgo Capgo
Classification
- Weakness
-
- CWE-770 Allocation of Resources Without Limits or Throttling
References
-
github.com
/Cap-go/capgo/security/advisories/GHSA-q52j-ggvx-cr4v
vendor-advisory, exploit
-
vulncheck.com
/advisories/capgo-plan-bypass-via-unrestricted-attachment-upload-endpoint
third-party-advisory
Sources
- CVE List CVE-2026-56309
- NVD CVE-2026-56309
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.