CVE-2024-1931

HIGH

Unbound 1.18.0-1.19.1 - Denial of Service via EDE Record Trimming Infinite Loop

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-2024-1931. PoCs published by passer12.

AI-analyzed exploit summary This repository provides a Dockerized environment to reproduce CVE-2024-1931, a DoS vulnerability in Unbound DNS resolver. The exploit script triggers the vulnerability by sending a crafted DNS query with specific flags, causing the service to crash.

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.

Exploits (1)

nomisec WORKING POC 1 stars
by passer12 · poc
https://github.com/passer12/CVE-2024-1931-reproduction

This repository provides a Dockerized environment to reproduce CVE-2024-1931, a DoS vulnerability in Unbound DNS resolver. The exploit script triggers the vulnerability by sending a crafted DNS query with specific flags, causing the service to crash.

Classification
Working Poc 90%
Attack Type
Dos
Complexity
Moderate
Reliability
Reliable
Target: Unbound DNS resolver version 1.19.1
No auth needed
Prerequisites: Docker environment · Unbound DNS resolver version 1.19.1
devstral-2 · analyzed Feb 19, 2026 Full analysis →

Scores

CVSS v3 7.5
EPSS 0.0252
EPSS Percentile 82.7%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CISA SSVC

Vulnrichment
Exploitation none
Automatable yes
Technical Impact partial

Details

CWE
CWE-835
Status published
Products (4)
fedoraproject/fedora 38
fedoraproject/fedora 39
fedoraproject/fedora 40
nlnetlabs/unbound 1.18.0 - 1.19.2
Published Mar 07, 2024
Tracked Since Feb 18, 2026