CVE-2024-1931 Denial of service when trimming EDE text on positive replies

What is CVE-2024-1931?

CVE-2024-1931 is a high-severity denial of service vulnerability in Fedoraproject Fedora, published on 7 Mar 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

NLnet Labs Unbound version 1.18.0 up to and including version 1.19.1 contain a vulnerability that can cause denial of service by a certain code path that can lead to an infinite loop. Unbound 1.18.0 introduced a feature that removes EDE records from responses with size higher than the client's advertised buffer size. Before removing all the EDE records however, it would try to see if trimming the extra text fields on those records would result in an acceptable size while still retaining the EDE codes. Due to an unchecked condition, the code that trims the text of the EDE records could loop indefinitely. This happens when Unbound would reply with attached EDE information on a positive reply and the client's buffer size is smaller than the needed space to include EDE records. The vulnerability can only be triggered when the 'ede: yes' option is used; non default configuration. From version 1.19.2 on, the code is fixed to avoid looping indefinitely.

Weakness: CWE-835

Which versions are affected by CVE-2024-1931?

It affects 2 products.

Products include Fedoraproject Fedora, Nlnetlabs Unbound.

How do I fix CVE-2024-1931?

Upgrade to a fixed version.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2024-1931 being exploited?

There is no known exploitation of CVE-2024-1931 in the wild and no public exploit code.

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• CVE-2019-5544 VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow Exploited Critical 9.8
• CVE-2024-4947 Google Chromium V8 Type Confusion Exploited Critical 9.6
• CVE-2024-4671 Google Chromium Visuals Use-After-Free Exploited Critical 9.6

All Fedoraproject Fedora vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as ALPINE-CVE-2024-1931, DEBIAN-CVE-2024-1931, GHSA-q63v-rwfp-q5p2, UBUNTU-CVE-2024-1931, openSUSE-SU-2024:13762-1.