# CVE-2026-2742: Unauthorized session creation via reserved framework path access > Attackers can bypass authentication and create unauthorized sessions by accessing reserved framework paths without a trailing slash in Vaadin applications using Spring Security. - **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:L/S:N/AU:Y/R:A/V:D/RE:L/U:Amber`) - **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:** 10 Mar 2026 - **Updated:** 16 Mar 2026 - **Also known as:** GHSA-rjgh-wgc7-m37j ## What is CVE-2026-2742? CVE-2026-2742 is a medium-severity authentication bypass vulnerability in vaadin flow, published on 10 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim. ### Official description An authentication bypass vulnerability exists in Vaadin 14.0.0 through 14.14.0, 23.0.0 through 23.6.6, 24.0.0 through 24.9.7 and 25.0.0 through 25.0.1, applications using Spring Security due to inconsistent path pattern matching of reserved framework paths. Accessing the /VAADIN endpoint without a trailing slash bypasses security filters, and allowing unauthenticated users to trigger framework initialization and create sessions without proper authorization. Users of affected versions using Spring Security should upgrade as follows: 14.0.0-14.14.0 upgrade to 14.14.1, 23.0.0-23.6.6 to 23.6.7, 24.0.0 - 24.9.7 to 24.9.8, and 25.0.0-25.0.1 upgrade to 25.0.2 or newer. Please note that Vaadin versions 10-13 and 15-22 are no longer supported and you should update either to the latest 14, 23, 24, 25 version. Weakness: CWE-284 (Improper Access Control) ## Which versions are affected by CVE-2026-2742? 16 open source packages ship an affected version, including com.vaadin:flow-server and com.vaadin:vaadin. It affects 1 product. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `com.vaadin:flow-server` | Maven | All versions | 14.14.1 | | `com.vaadin:flow-server` | Maven | All versions | 14.14.1 | | `com.vaadin:flow-server` | Maven | From 23.0.0 | 23.6.7 | | `com.vaadin:flow-server` | Maven | From 23.0.0 | 23.6.7 | | `com.vaadin:flow-server` | Maven | From 24.0.0 | 24.9.8 | | `com.vaadin:flow-server` | Maven | From 24.0.0 | 24.9.8 | | `com.vaadin:flow-server` | Maven | From 25.0.0 | 25.0.2 | | `com.vaadin:flow-server` | Maven | From 25.0.0 | 25.0.2 | | `com.vaadin:vaadin` | Maven | All versions | 14.14.1 | | `com.vaadin:vaadin` | Maven | All versions | 14.14.1 | | `com.vaadin:vaadin` | Maven | From 23.0.0 | 23.6.7 | | `com.vaadin:vaadin` | Maven | From 23.0.0 | 23.6.7 | | `com.vaadin:vaadin` | Maven | From 24.0.0 | 24.9.8 | | `com.vaadin:vaadin` | Maven | From 24.0.0 | 24.9.8 | | `com.vaadin:vaadin` | Maven | From 25.0.0 | 25.0.2 | | `com.vaadin:vaadin` | Maven | From 25.0.0 | 25.0.2 | Products: Vaadin Vaadin. ## How do I fix CVE-2026-2742? Upgrade com.vaadin:flow-server to a fixed version for your release line: 14.14.1, 23.6.7, 24.9.8 or 25.0.2. ## Is CVE-2026-2742 being exploited? There is no known exploitation of CVE-2026-2742 in the wild and no public exploit code. ## Other vulnerabilities in vaadin flow - [CVE-2021-31409](https://insights.sbomify.com/CVE-2021-31409/): Server session is not invalidated when logout() helper method of Authentication module is used in Vaadin 18-19 (high 7.5) - [CVE-2020-36320](https://insights.sbomify.com/CVE-2020-36320/): Regular expression Denial of Service (ReDoS) in EmailValidator class in Vaadin 7 (high 7.5) - [CVE-2021-33611](https://insights.sbomify.com/CVE-2021-33611/): Reflected cross-site scripting in vaadin-menu-bar webjar resources in Vaadin 14 (medium 6.1) - [CVE-2023-25499](https://insights.sbomify.com/CVE-2023-25499/): Possible information disclosure in non visible components (medium 5.7) - [CVE-2022-29567](https://insights.sbomify.com/CVE-2022-29567/): Possible information disclosure inside TreeGrid component with default data provider (medium 5.7) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-2742 and fix it if it is affected. What it is: CVE-2026-2742 is a medium-severity authentication bypass vulnerability in vaadin flow, published on 10 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim. Exploitation: There is no known exploitation of CVE-2026-2742 in the wild and no public exploit code. Affected packages and fixed versions: - com.vaadin:flow-server (Maven): affected all versions; fixed in 14.14.1 - com.vaadin:flow-server (Maven): affected all versions; fixed in 14.14.1 - com.vaadin:flow-server (Maven): affected from 23.0.0; fixed in 23.6.7 - com.vaadin:flow-server (Maven): affected from 23.0.0; fixed in 23.6.7 - com.vaadin:flow-server (Maven): affected from 24.0.0; fixed in 24.9.8 - com.vaadin:flow-server (Maven): affected from 24.0.0; fixed in 24.9.8 - com.vaadin:flow-server (Maven): affected from 25.0.0; fixed in 25.0.2 - com.vaadin:flow-server (Maven): affected from 25.0.0; fixed in 25.0.2 - com.vaadin:vaadin (Maven): affected all versions; fixed in 14.14.1 - com.vaadin:vaadin (Maven): affected all versions; fixed in 14.14.1 - com.vaadin:vaadin (Maven): affected from 23.0.0; fixed in 23.6.7 - com.vaadin:vaadin (Maven): affected from 23.0.0; fixed in 23.6.7 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-2026-2742/ (Markdown: https://insights.sbomify.com/CVE-2026-2742/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-2742 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-2742 - OSV: https://osv.dev/vulnerability/CVE-2026-2742 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-2742/ Summaries are generated and may contain mistakes; the official description above is the record.