Centrifugo: Dynamic JWKS key cache keyed only by `kid` allows cross-issuer JWT authentication bypass
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- High
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- High · High · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-347.
Summary
Centrifugo is an open-source scalable real-time messaging server. Prior to 6.8.1, Centrifugo dynamic JWKS endpoint verification could reuse a key for one allowed issuer to verify a JWT for another allowed issuer because the JWKS cache and singleflight lookup were keyed only by JWT header kid, not by the resolved JWKS endpoint, issuer, audience, or trust-domain namespace, affecting client.token.jwks_public_endpoint, client.subscription_token.jwks_public_endpoint, internal/jwks/cache.go, and internal/jwks/manager.go. This issue is fixed in version 6.8.1.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- No
- Technical impact
- Total
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 |
|---|---|---|---|---|---|
| centrifugal | centrifugo | before 6.8.1 | 6.8.1 | Patch available | CNA |
| — | github.com/centrifugal/centrifugo/v6 (Go) | before 6.8.1 | 6.8.1 | Patch available | GHSA-g6vg-wj8f-48cj |
| — | github.com/centrifugal/centrifugo/v5 (Go) | up to 5.4.9 | — | No fix listed | GHSA-g6vg-wj8f-48cj |
| — | github.com/centrifugal/centrifugo/v4 (Go) | up to 4.1.5 | — | No fix listed | GHSA-g6vg-wj8f-48cj |
| — | github.com/centrifugal/centrifugo/v3 (Go) | up to 3.2.3 | — | No fix listed | GHSA-g6vg-wj8f-48cj |
| — | github.com/centrifugal/centrifugo (Go) | up to 2.4.0 | — | No fix listed | GHSA-g6vg-wj8f-48cj |
- centrifugo Vendorcentrifugal Affected before 6.8.1 Fixed in 6.8.1 Patch available CNA
- github.com/centrifugal/centrifugo/v6 (Go) Vendor— Affected before 6.8.1 Fixed in 6.8.1 Patch available GHSA-g6vg-wj8f-48cj
- github.com/centrifugal/centrifugo/v5 (Go) Vendor— Affected up to 5.4.9 Fixed in — No fix listed GHSA-g6vg-wj8f-48cj
- github.com/centrifugal/centrifugo/v4 (Go) Vendor— Affected up to 4.1.5 Fixed in — No fix listed GHSA-g6vg-wj8f-48cj
- github.com/centrifugal/centrifugo/v3 (Go) Vendor— Affected up to 3.2.3 Fixed in — No fix listed GHSA-g6vg-wj8f-48cj
- github.com/centrifugal/centrifugo (Go) Vendor— Affected up to 2.4.0 Fixed in — No fix listed GHSA-g6vg-wj8f-48cj
Remediation
- Fix · CNA centrifugo (centrifugal) Fixed in 6.8.1
- Fix · GHSA-g6vg-wj8f-48cj github.com/centrifugal/centrifugo/v6 (Go) Fixed in 6.8.1 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2026-49998
- 2026-10-03 Alias added: GHSA-g6vg-wj8f-48cj
References
Other 5
- https://github.com/centrifugal/centrifugo/security/advisories/GHSA-g6vg-wj8f-48cj
- https://github.com/centrifugal/centrifugo/pull/1142
- https://github.com/centrifugal/centrifugo/commit/15d785015c6f318c1b68ea40b813699c9f8bd2c4
- https://github.com/centrifugal/centrifugo/releases/tag/v6.8.1
- https://github.com/centrifugal/centrifugo
More centrifugal vulnerabilities
- TI-2026-24830 Centrifugo: SSRF via unverified JWT claims interpolated into dynamic JWKS endpoint URL CVSS 3.1CRITICAL 9.3
- TI-2026-50096 Centrifugo: Client-forgeable headers emulation lets any client spoof headers forwarded to proxy backends CVSS 3.1CRITICAL 9.1
- TI-2026-44987 Centrifugo: Decompression bomb DoS via permessage-deflate in unidirectional WebSocket transport CVSS 4.0HIGH 8.7
Sources
- CVE-2026-49998 · CVE Program
- CVE-2026-49998 · NVD
- FIRST EPSS
- GHSA-g6vg-wj8f-48cj · GitHub Advisory Database · CC BY 4.0
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