# CVE-2026-49998: Centrifugo: Dynamic JWKS key cache keyed only by `kid` allows cross-issuer JWT authentication bypass > Attackers can bypass JWT authentication by exploiting a JWKS cache flaw that reuses keys across different issuers in Centrifugo. - **Severity:** High 8.2 (`CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:N`) - **Exploited in the wild:** Not known - **Login needed:** Any signed-in user - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 16 Jul 2026 - **Updated:** 17 Jul 2026 - **Also known as:** GHSA-g6vg-wj8f-48cj, GO-2026-5872 ## What is CVE-2026-49998? CVE-2026-49998 is a high-severity authentication bypass vulnerability in centrifugal centrifugo, published on 16 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim. ### Official description 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. Weakness: CWE-347 (Improper Verification of Cryptographic Signature) ## Which versions are affected by CVE-2026-49998? 15 open source packages ship an affected version, including github.com/centrifugal/centrifugo, github.com/centrifugal/centrifugo/v3 and github.com/centrifugal/centrifugo/v4. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `github.com/centrifugal/centrifugo` | Go | All versions | None | | `github.com/centrifugal/centrifugo` | Go | All versions to 2.4.0 | None | | `github.com/centrifugal/centrifugo` | Go | All versions to 2.4.0 | None | | `github.com/centrifugal/centrifugo/v3` | Go | All versions | None | | `github.com/centrifugal/centrifugo/v3` | Go | All versions to 3.2.3 | None | | `github.com/centrifugal/centrifugo/v3` | Go | All versions to 3.2.3 | None | | `github.com/centrifugal/centrifugo/v4` | Go | All versions | None | | `github.com/centrifugal/centrifugo/v4` | Go | All versions to 4.1.5 | None | | `github.com/centrifugal/centrifugo/v4` | Go | All versions to 4.1.5 | None | | `github.com/centrifugal/centrifugo/v5` | Go | All versions | None | | `github.com/centrifugal/centrifugo/v5` | Go | All versions to 5.4.9 | None | | `github.com/centrifugal/centrifugo/v5` | Go | All versions to 5.4.9 | None | | `github.com/centrifugal/centrifugo/v6` | Go | All versions | 6.8.1 | | `github.com/centrifugal/centrifugo/v6` | Go | All versions | 6.8.1 | | `github.com/centrifugal/centrifugo/v6` | Go | All versions | 6.8.1 | ## How do I fix CVE-2026-49998? Upgrade to a fixed version. ## Is CVE-2026-49998 being exploited? It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-49998 exists. ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-49998 and fix it if it is affected. What it is: CVE-2026-49998 is a high-severity authentication bypass vulnerability in centrifugal centrifugo, published on 16 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim. Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-49998 exists. Affected packages and fixed versions: - github.com/centrifugal/centrifugo (Go): affected all versions; no fix listed - github.com/centrifugal/centrifugo (Go): affected all versions up to 2.4.0; no fix listed - github.com/centrifugal/centrifugo (Go): affected all versions up to 2.4.0; no fix listed - github.com/centrifugal/centrifugo/v3 (Go): affected all versions; no fix listed - github.com/centrifugal/centrifugo/v3 (Go): affected all versions up to 3.2.3; no fix listed - github.com/centrifugal/centrifugo/v3 (Go): affected all versions up to 3.2.3; no fix listed - github.com/centrifugal/centrifugo/v4 (Go): affected all versions; no fix listed - github.com/centrifugal/centrifugo/v4 (Go): affected all versions up to 4.1.5; no fix listed - github.com/centrifugal/centrifugo/v4 (Go): affected all versions up to 4.1.5; no fix listed - github.com/centrifugal/centrifugo/v5 (Go): affected all versions; no fix listed - github.com/centrifugal/centrifugo/v5 (Go): affected all versions up to 5.4.9; no fix listed - github.com/centrifugal/centrifugo/v5 (Go): affected all versions up to 5.4.9; no fix listed Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2026-49998/ (Markdown: https://insights.sbomify.com/CVE-2026-49998/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-49998 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-49998 - OSV: https://osv.dev/vulnerability/CVE-2026-49998 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-49998/ Summaries are generated and may contain mistakes; the official description above is the record.