Summary
Synopsis: Streamlit open source publicizes a prior security fix implemented in 2021. The vulnerability affected Streamlit versions between 0.63.0 and 0.80.0 (inclusive) and was patched on April 21, 2021. If you are using Streamlit with version before 0.63.0 or after 0.80.0, no action is required.
1. Impacted Products
Streamilt Open Source versions between 0.63.0 and 0.80.0.
2. Introduction
On April 21, 2021, Streamlit merged a patch that fixed a cross-site scripting (XSS) vulnerability in the Streamlit open source library, without an associated public advisory. The vulnerability affected Streamlit versions between 0.63.0 and 0.80.0 (inclusive), which are no longer supported. We recommend using the latest version of our library, but so long as you are not using an affected Streamlit version, no action is required.
3. Cross Site Scripting Vulnerability
3.1 Description
On April 20, 2021, Streamlit was informed via our support forum about a XSS vulnerability in the open source library. We fixed and merged a patch remediating the vulnerability on April 21st, 2021. The issue was determined to be in the moderate severity range with a maximum CVSSv3 base score of 5.9
3.2 Scenarios and attack vector(s)
Users of hosted Streamlit app(s) were vulnerable to a reflected XSS vulnerability. An attacker could craft a malicious URL with Javascript payloads to a Streamlit app. The attacker could then trick the user into visiting the malicious URL and, if successful, the server would render the malicious javascript payload as-is, leading to an XSS.
3.3 Our response
Streamlit fixed and merged a patch for this vulnerability on April 21, 2021. The vulnerability was fixed within 24hrs of notification to Streamlit.
3.4 Resolution
The vulnerability has been fixed in all Streamlit versions released since April 21, 2021. The affected versions, those between 0.63.0 and 0.80.0 (inclusive), are no longer supported. We recommend always using supported versions of the Streamlit open source library. Version 1.19.0 is current as of this advisory.
4. Contact
Please contact [email protected] if you have any questions regarding this advisory. If you discover a security vulnerability in one of our products or websites, please report the issue to HackerOne. For more information, please see our Vulnerability Disclosure Policy.
Impact
Untrusted input is rendered as active markup in a victim's browser, which can run script in their session. Typical impact: session or credential theft, and actions taken as the user.
CVE-2023-27494 has a CVSS score of 5.9 (Medium). The vector is network-reachable, no privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.81.0); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Remediation advice
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2023-27494? CVE-2023-27494 is a medium-severity cross-site scripting (XSS) vulnerability in streamlit (pip), affecting versions >= 0.63.0, < 0.81.0. It is fixed in 0.81.0. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
- How severe is CVE-2023-27494? CVE-2023-27494 has a CVSS score of 5.9 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of streamlit are affected by CVE-2023-27494? streamlit (pip) versions >= 0.63.0, < 0.81.0 is affected.
- Is there a fix for CVE-2023-27494? Yes. CVE-2023-27494 is fixed in 0.81.0. Upgrade to this version or later.
- Is CVE-2023-27494 exploitable, and should I be worried? Whether CVE-2023-27494 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2023-27494 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2023-27494? Upgrade
streamlitto 0.81.0 or later.