Summary
CSRF attack via CORS preflight requests with Spring MVC or Spring WebFlux
Spring Framework, versions 5.2.x prior to 5.2.3 are vulnerable to CSRF attacks through CORS preflight requests that target Spring MVC (spring-webmvc module) or Spring WebFlux (spring-webflux module) endpoints. Only non-authenticated endpoints are vulnerable because preflight requests should not include credentials and therefore requests should fail authentication. However a notable exception to this are Chrome based browsers when using client certificates for authentication since Chrome sends TLS client certificates in CORS preflight requests in violation of spec requirements. No HTTP body can be sent or received as a result of this attack.
Impact
A victim's authenticated browser session is used to submit forged requests to an application that cannot distinguish them from legitimate ones. Typical impact: state-changing actions performed as the victim without their consent.
CVE-2020-5397 has a CVSS score of 5.3 (Medium). The vector is network-reachable, no privileges required, and no user interaction. 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 (5.2.3); 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.
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org.springframework:spring-webmvc to 5.2.3 or later; org.springframework:spring-webflux to 5.2.3 or later
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2020-5397? CVE-2020-5397 is a medium-severity cross-site request forgery (CSRF) vulnerability in org.springframework:spring-webmvc (maven), affecting versions >= 5.2.0, < 5.2.3. It is fixed in 5.2.3. A victim's authenticated browser session is used to submit forged requests to an application that cannot distinguish them from legitimate ones.
- How severe is CVE-2020-5397? CVE-2020-5397 has a CVSS score of 5.3 (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 packages are affected by CVE-2020-5397?
org.springframework:spring-webmvc(maven) (versions >= 5.2.0, < 5.2.3)org.springframework:spring-webflux(maven) (versions >= 5.2.0, < 5.2.3)
- Is there a fix for CVE-2020-5397? Yes. CVE-2020-5397 is fixed in 5.2.3. Upgrade to this version or later.
- Is CVE-2020-5397 exploitable, and should I be worried? Whether CVE-2020-5397 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-2020-5397 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-2020-5397?
- Upgrade
org.springframework:spring-webmvcto 5.2.3 or later - Upgrade
org.springframework:spring-webfluxto 5.2.3 or later
- Upgrade