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

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.

Published: 2024-03-07 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2024-1931 is rated Moderate Risk (54.7/100): CVSS High severity, with medium exploitation likelihood (EPSS 2.52%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2024-1931

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 6.75% 2.52% -4.24%
2 2025-11-21 24.65% 6.75% -17.90%
3 2025-11-18 — 24.65% —

Full EPSS history (19 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2024-1931

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]

Weakness enumeration for CVE-2024-1931

OS Trackers for CVE-2024-1931

vendor priority summary link
alpine — CVE-2024-1931: 1 source package rows (unbound); 12 state rows across 7 repos (3.17-main, 3.18-main, 3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 7, open 5. https://security.alpinelinux.org/vuln/CVE-2024-1931
debian unimportant CVE-2024-1931 unimportant priority: Debian including 1 source packages (unbound), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2024-1931
redhat medium — https://access.redhat.com/security/cve/CVE-2024-1931
suse medium CVE-2024-1931 severity moderate: SUSE including 25 source package names (latest:libopenssl3-3.1.4-slfo.1.1_4.1, latest:openssl-3-3.1.4-slfo.1.1_4.1, …), 154 product×package rows across 50 product lines (Container suse/sl-micro/6.0/baremetal-os-container, Container suse/sl-micro/6.0/base-os-container, … (50 product lines)): Known Not Affected 89, Fixed 65. https://www.suse.com/security/cve/CVE-2024-1931/
ubuntu medium CVE-2024-1931 medium priority: Ubuntu including 1 source packages (unbound), 8 status rows across 8 suites (bionic, focal, jammy, mantic, noble, trusty, upstream, xenial): not-affected 6, released 2. https://ubuntu.com/security/CVE-2024-1931

Affected software / configurations for CVE-2024-1931

Vendor Product Version Raw CPE
nlnetlabs unbound >= 1.18.0, < 1.19.2 cpe:2.3:a:nlnetlabs:unbound:*:*:*:*:*:*:*:*
fedoraproject fedora 38 cpe:2.3:o:fedoraproject:fedora:38:*:*:*:*:*:*:*
fedoraproject fedora 39 cpe:2.3:o:fedoraproject:fedora:39:*:*:*:*:*:*:*
fedoraproject fedora 40 cpe:2.3:o:fedoraproject:fedora:40:*:*:*:*:*:*:*

References for CVE-2024-1931

cvelogic Threat Intelligence