# What is CVE-2024-27309? > CVE-2024-27309 is a high-severity flaw (CVSS 7.4) in Kafka from Apache, published on 12 April 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 1.1%. If you run an affected version, plan in the vendor’s fix. Canonical page: https://www.precursorintelligence.com/what-is/cve-2024-27309 ## At a glance - **Verdict:** Plan it in. No sign of exploitation and a low forecast. Patch it in your normal update cycle. - **Precursor Intelligence risk score:** 48 out of 100 (Medium); action: Plan remediation. Kept up to date as the evidence changes. - **Severity:** High (CVSS 7.4 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:** 1.1% (latest exploit-likelihood forecast) - **Published:** 12 April 2024 - **Record last updated:** 17 June 2026 - **Main product:** Kafka from Apache - **Affected products:** 1 ## What is CVE-2024-27309? 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 and change data. ### The official description While an Apache Kafka cluster is being migrated from ZooKeeper mode to KRaft mode, in some cases ACLs will not be correctly enforced. Two preconditions are needed to trigger the bug: 1. The administrator decides to remove an ACL 2. The resource associated with the removed ACL continues to have two or more other ACLs associated with it after the removal. When those two preconditions are met, Kafka will treat the resource as if it had only one ACL associated with it after the removal, rather than the two or more that would be correct. The incorrect condition is cleared by removing all brokers in ZK mode, or by adding a new ACL to the affected resource. Once the migration is completed, there is no metadata loss (the ACLs all remain). The full impact depends on the ACLs in use. If only ALLOW ACLs were configured during the migration, the impact would be limited to availability impact. if DENY ACLs were configured, the impact could include confidentiality and integrity impact depending on the ACLs configured, as the DENY ACLs might be ignored due to this vulnerability during the migration period. ### What kind of flaw is it? - CWE-863: Incorrect Authorization ### How an attack on it works - Where an attacker can be: Anywhere on the internet - How hard it is to pull off: Hard: conditions must line up - Login needed first: No login needed - Does someone have to click: No, nobody has to do anything - What an attacker gets: Can read data and change data Severity vector: `CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N` ## Is CVE-2024-27309 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 1.1%. That can change at any time, which is why we keep watching. Exploit likelihood over the last 7 days: 1.1%, 1.1%, 1.1%, 1.1%, 1.1%, 1.1%, 1.1%. ### Timeline - 12 April 2024: Published - 17 June 2026: Record last updated ### How Precursor Intelligence ranks it CVE-2024-27309 scores **48 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-2024-27309? The published record lists 1 product. - [Kafka](https://www.precursorintelligence.com/product/apache/kafka) by [Apache](https://www.precursorintelligence.com/vendors/apache) (Application): 3.5.0 to 3.6.1 ## How do I fix CVE-2024-27309? 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/6536rmzyg076lzzdw2xdktvnz163mjpy) (Mailing list, Vendor advisory) - [openwall.com](http://www.openwall.com/lists/oss-security/2024/04/12/3) (Mailing list, Third-party advisory) - [security.netapp.com](https://security.netapp.com/advisory/ntap-20240705-0002/) (Third-party advisory) ## Questions ### What is CVE-2024-27309? CVE-2024-27309 is a high-severity flaw in Kafka from Apache, published on 12 April 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 and change data. ### How serious is CVE-2024-27309? It scores 7.4 out of 10 on the CVSS severity scale, which is high. Our risk score for CVE-2024-27309 is 48 out of 100, which is Medium. Its action is "Plan remediation". No sign of exploitation and a low forecast. Patch it in your normal update cycle. ### Is CVE-2024-27309 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 1.1%. That can change at any time, which is why we keep watching. ### Which versions does CVE-2024-27309 affect? For Kafka from Apache: 3.5.0 to 3.6.1. ### How do I fix CVE-2024-27309? 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-2024-27309 affect you? 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