CVE-2024-1931

Denial of service when trimming EDE text on positive replies

Published Mar 7, 2024 CVSS 3.1 · 7.5 High EPSS 2.5% KEV · Not listed
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.

Remediation

Vendor Solution

This issue is fixed in 1.19.2 and all later versions. For the vulnerable versions 1.18.0 up to and including 1.19.1, the option 'ede: no' (default configuration) is also a solution as it does not exercise the vulnerable code path.

Tracking

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Advisories

Source ID Title
EUVD EUVD EUVD-2024-17653 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.
History
Type Values Removed Values Added
Metrics epss

{'score': 0.06753}

epss

{'score': 0.0822}

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Fedoraproject
Fedoraproject fedora
Nlnetlabs
Nlnetlabs unbound
CPEs cpe:2.3:a:nlnetlabs:unbound:*:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:38:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:39:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:40:*:*:*:*:*:*:*
Vendors & Products Fedoraproject
Fedoraproject fedora
Nlnetlabs
Nlnetlabs unbound
Weaknesses

Sources

Status
PUBLISHED
Assigner
NLnet Labs
Published
Updated
Feb 13, 2025, 5:32 PM
Reserved
Feb 27, 2024, 1:43 PM
Status
Analyzed
Published
Mar 7, 2024, 10:15 AM
Modified
Jun 17, 2026, 7:05 AM
Severity
Moderate
Public date
Mar 7, 2024, 12:00 AM