# What is CVE-2024-56337? > CVE-2024-56337 is a critical-severity flaw (CVSS 9.8) in Tomcat from Apache, published on 20 December 2024. It is not on the list of flaws known to be exploited today. The latest forecast puts its chance of use in the next 30 days at 9.0%. If you run an affected version, plan in the vendor’s fix. Canonical page: https://www.precursorintelligence.com/what-is/cve-2024-56337 ## At a glance - **Verdict:** Fix this soon. Not confirmed as exploited yet, but serious or likely enough that it should not wait for a quiet month. - **Precursor Intelligence risk score:** 56 out of 100 (Medium); action: Plan remediation. Kept up to date as the evidence changes. - **Severity:** Critical (CVSS 9.8 out of 10) - **Known to be exploited:** No, not on the list of flaws known to be exploited today - **Chance of use in the next 30 days:** 9.0% (latest exploit-likelihood forecast) - **Published:** 20 December 2024 - **Record last updated:** 3 November 2025 - **Main product:** Tomcat from Apache - **Affected products:** 2 ## What is CVE-2024-56337? In plain terms It can be attacked from anywhere on the internet without logging in, and nobody has to click anything. If it works, the attacker can read data, change data and take it offline. ### The official description Time-of-check Time-of-use (TOCTOU) Race Condition vulnerability in Apache Tomcat. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.1, from 10.1.0-M1 through 10.1.33, from 9.0.0.M1 through 9.0.97. The following versions were EOL at the time the CVE was created but are known to be affected: 8.5.0 though 8.5.100. Other, older, EOL versions may also be affected. The mitigation for CVE-2024-50379 was incomplete. Users running Tomcat on a case insensitive file system with the default servlet write enabled (readonly initialisation parameter set to the non-default value of false) may need additional configuration to fully mitigate CVE-2024-50379 depending on which version of Java they are using with Tomcat: - running on Java 8 or Java 11: the system property sun.io.useCanonCaches must be explicitly set to false (it defaults to true) - running on Java 17: the system property sun.io.useCanonCaches, if set, must be set to false (it defaults to false) - running on Java 21 onwards: no further configuration is required (the system property and the problematic cache have been removed) Tomcat 11.0.3, 10.1.35 and 9.0.99 onwards will include checks that sun.io.useCanonCaches is set appropriately before allowing the default servlet to be write enabled on a case insensitive file system. Tomcat will also set sun.io.useCanonCaches to false by default where it can. ### What kind of flaw is it? - CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition ### How an attack on it works - Where an attacker can be: Anywhere on the internet - How hard it is to pull off: Easy: no special conditions - Login needed first: No login needed - Does someone have to click: No, nobody has to do anything - What an attacker gets: Can read data, change data and take it offline Severity vector: `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H` ## Is CVE-2024-56337 being exploited? Not that we know of It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 9.0%. That can change at any time, which is why we keep watching. Exploit likelihood over the last 7 days: 9.0%, 9.0%, 9.0%, 9.0%, 9.0%, 9.0%, 9.0%. ### Timeline - 20 December 2024: Published - 2 October 2025: Exploit likelihood fell - 5 October 2025: Exploit likelihood jumped - 3 November 2025: Record last updated ### How Precursor Intelligence ranks it CVE-2024-56337 scores **56 out of 100 (Medium)**, with the action "Plan remediation". Every published flaw gets a risk score from 0 to 100, kept up to date as the evidence changes. Four things go into the score, from the one that counts most to the ones that count less: - Evidence it is being exploited: biggest factor - How severe it is: strong factor - How widely exposed it is: smaller factor - Threat activity around it: smaller factor 85 and above is Critical. Anything confirmed as exploited is always marked for an emergency patch, whatever its score. When this flaw matches software you track, it lands in your list with its score and the reasons behind it. ## Who is affected by CVE-2024-56337? The published record lists 2 products. Versions are as published: "9.0.0 to before 9.0.98" means from 9.0.0 up to, but not including, 9.0.98. - [Tomcat](https://www.precursorintelligence.com/product/apache/tomcat) by [Apache](https://www.precursorintelligence.com/vendors/apache) (Application): 9.0.0 to before 9.0.98, 10.1.0 to before 10.1.34, 11.0.0 to before 11.0.2 - [Bootstrap OS](https://www.precursorintelligence.com/product/netapp/bootstrap_os) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Operating system): version not specified ## How do I fix CVE-2024-56337? 1. **Check whether you run it.** Compare your versions with the affected products above. Not sure what you run? Precursor Intelligence can work it out from your public website, or you can pick it from a list. 2. **Apply the vendor’s fix.** Install the update named in the vendor’s advisory. We’ve put the advisory first in the list. 3. **If you can’t patch today.** Follow any mitigation the vendor publishes, and limit who can reach the affected system from the internet until the update is in. 4. **Keep an eye on it.** Track the product and we tell you as soon as we spot this flaw on the list of exploited flaws, or a jump in its exploit likelihood. ### References - [lists.apache.org](https://lists.apache.org/thread/b2b9qrgjrz1kvo4ym8y2wkfdvwoq6qbp) (Mailing list, Vendor advisory) - [cve.org](https://www.cve.org/CVERecord?id=CVE-2024-50379) (Third-party advisory) - [lists.debian.org](https://lists.debian.org/debian-lts-announce/2025/01/msg00009.html) - [security.netapp.com](https://security.netapp.com/advisory/ntap-20250103-0002/) (Third-party advisory) ## Questions ### What is CVE-2024-56337? CVE-2024-56337 is a critical-severity flaw in Tomcat from Apache, published on 20 December 2024. It can be attacked from anywhere on the internet without logging in, and nobody has to click anything. If it works, the attacker can read data, change data and take it offline. ### How serious is CVE-2024-56337? It scores 9.8 out of 10 on the CVSS severity scale, which is critical. Our risk score for CVE-2024-56337 is 56 out of 100, which is Medium. Its action is "Plan remediation". Not confirmed as exploited yet, but serious or likely enough that it should not wait for a quiet month. ### Is CVE-2024-56337 being exploited? It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 9.0%. That can change at any time, which is why we keep watching. ### Which versions does CVE-2024-56337 affect? For Tomcat from Apache: 9.0.0 to before 9.0.98, 10.1.0 to before 10.1.34, 11.0.0 to before 11.0.2. The record lists 2 products in all, each with its versions, under "Who is affected" on this page. ### How do I fix CVE-2024-56337? Install the update the vendor names in its advisory, linked first under "How do I fix" on this page. If you can't patch today, follow the vendor's mitigation and limit who can reach the affected system from the internet. ## Does CVE-2024-56337 affect you? Precursor Intelligence keeps checking for you: - **Tell us what you run.** Pick your software from a list, or let us work it out from your website. - **We match it to every flaw.** Over 400,000 published flaws, checked against your list. - **Ranked by real-world risk.** Every flaw gets a 0 to 100 risk score, kept up to date, led by evidence criminals are using it. - **Told as soon as we know.** An alert by email, in the app or by webhook to your own tools. Start free (no card, nothing to install): https://www.precursorintelligence.com/register Book a demo: https://www.precursorintelligence.com/contact