# CVE-2023-33962: JStachio XSS vulnerability: Unescaped single quotes > Attackers can inject malicious JavaScript via unescaped single quotes in JStachio templates, leading to session hijacking or data theft. - **Severity:** Medium 5.4 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N`) - **Exploited in the wild:** Not known - **Login needed:** Any signed-in user - **Attackable:** Over the internet - **Victim action needed:** A user has to click or open something - **Fix available:** Yes - **Published:** 30 May 2023 - **Updated:** 10 Jan 2025 - **Also known as:** GHSA-gwxv-jv83-6qjr ## What is CVE-2023-33962? CVE-2023-33962 is a medium-severity cross-site scripting vulnerability in jstachio, published on 30 May 2023. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link. ### Official description JStachio is a type-safe Java Mustache templating engine. Prior to version 1.0.1, JStachio fails to escape single quotes `'` in HTML, allowing an attacker to inject malicious code. This vulnerability can be exploited by an attacker to execute arbitrary JavaScript code in the context of other users visiting pages that use this template engine. This can lead to various consequences, including session hijacking, defacement of web pages, theft of sensitive information, or even the propagation of malware. Version 1.0.1 contains a patch for this issue. To mitigate this vulnerability, the template engine should properly escape special characters, including single quotes. Common practice is to escape `'` as `'`. As a workaround, users can avoid this issue by using only double quotes `"` for HTML attributes. Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation) ## Which versions are affected by CVE-2023-33962? 2 open source packages ship an affected version, including io.jstach:jstachio. It affects 1 product. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `io.jstach:jstachio` | Maven | All versions | 1.0.1 | | `io.jstach:jstachio` | Maven | All versions | 1.0.1 | Products: Jstachio Project Jstachio. ## How do I fix CVE-2023-33962? Upgrade io.jstach:jstachio to 1.0.1 or later. ## Is CVE-2023-33962 being exploited? It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-33962 exists. Public exploit code: - https://github.com/shoucheng3/jstachio__jstachio_CVE-2023-33962_1-0-0 (github_poc): https://github.com/shoucheng3/jstachio__jstachio_CVE-2023-33962_1-0-0 ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2023-33962 and fix it if it is affected. What it is: CVE-2023-33962 is a medium-severity cross-site scripting vulnerability in jstachio, published on 30 May 2023. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link. Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-33962 exists. Affected packages and fixed versions: - io.jstach:jstachio (Maven): affected all versions; fixed in 1.0.1 - io.jstach:jstachio (Maven): affected all versions; fixed in 1.0.1 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-2023-33962/ (Markdown: https://insights.sbomify.com/CVE-2023-33962/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2023-33962 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-33962 - OSV: https://osv.dev/vulnerability/CVE-2023-33962 --- From sbomify Insights: https://insights.sbomify.com/CVE-2023-33962/ Summaries are generated and may contain mistakes; the official description above is the record.