Improper access control in @koa/router
Priority HIGH 70CWE-284Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- Low · Low · Low
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub. Impact type from CWE-284.
Summary
Versions of the package @koa/router from 14.0.0 and before 15.0.0 are vulnerable to Access Control Bypass due to the middleware being silently dropped from the execution chain when the router prefix contains path parameters. Depending on what the skipped middleware was supposed to protect, an attacker could bypass authentication and authorization, evade rate limiting or bypass input sanitization.
Why it matters now
Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.0036 29th percentileScored 2026-11-07
Fix Fixed @koa/router: 15.0.0@koa/router (npm): 15.0.0
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | @koa/router | 14.0.0 to before 15.0.0 | 15.0.0 | Patch available | CNA |
| — | @koa/router (npm) | 14.0.0 to before 15.0.0 | 15.0.0 | Patch available | GHSA-47p6-69vm-vw6v |
- @koa/router Vendor— Affected 14.0.0 to before 15.0.0 Fixed in 15.0.0 Patch available CNA
- @koa/router (npm) Vendor— Affected 14.0.0 to before 15.0.0 Fixed in 15.0.0 Patch available GHSA-47p6-69vm-vw6v
Remediation
- Fix · CNA @koa/router Fixed in 15.0.0
- Fix · GHSA-47p6-69vm-vw6v @koa/router (npm) Fixed in 15.0.0 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2026-9495
- 2026-10-03 Alias added: GHSA-47p6-69vm-vw6v
References
Sources
- CVE-2026-9495 · CVE Program
- CVE-2026-9495 · NVD
- FIRST EPSS
- GHSA-47p6-69vm-vw6v · GitHub Advisory Database · CC BY 4.0
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