CVE-2026-49998Public exploitNetwork attack vectorHinoki check available

Cross-issuer authentication bypass via kid-only JWKS cache

Published Jul 16, 2026 · Updated Jul 16, 2026

Authentication bypass in Centrifugo before 6.8.1 allows remote authenticated users to impersonate users in another allowed issuer. The JWKS manager indexes its TTL cache and concurrent singleflight lookup only by the JWT kid header, allowing a key resolved for one issuer endpoint to verify a token claiming another issuer. Exploitation requires dynamic issuer- or audience-derived JWKS endpoints, a shared kid value, a valid token or signing key for one allowed issuer, and that issuer's key entering the cache first.

CVSS severity8.2
High
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Authentication bypass in Centrifugo before 6.8.1 allows remote authenticated users to impersonate users in another allowed issuer. The JWKS manager indexes its TTL cache and concurrent singleflight lookup only by the JWT kid header, allowing a key resolved for one issuer endpoint to verify a token claiming another issuer. Exploitation requires dynamic issuer- or audience-derived JWKS endpoints, a shared kid value, a valid token or signing key for one allowed issuer, and that issuer's key entering the cache first.

The record

CVE
CVE-2026-49998
Published
Jul 16, 2026
Updated
Jul 16, 2026
Vendor
Centrifugal Labs
Product
Centrifugo
Classifications
CWE-347, T1550.001
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 16, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 16, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 6.8.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Centrifugal Labs · Centrifugoversion=< 6.8.1

Published CVSS scores

8.2GitHubCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-347Improper Verification of Cryptographic Signature
T1550.001Application Access Token

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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