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Fencer Vulns
high 7.5

CVE-2024-1931 json

Denial of service when trimming EDE text on positive replies

published 2024-03-07 2 y ago modified 2026-06-17 4 mo ago also EUVD-2024-17653

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
2.5%
EPSS 2.5% chance of exploitation in 30 days, percentile 84%
public exploits
0
none known

Summary

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.

Patch / fix

  • NLnet Labs Unbound 1.19.2
  • nlnetlabs unbound 1.19.2
  • unbound Debian 14, Debian 13 1.19.2-1

debian advisories DEBIAN-CVE-2024-1931

  • unbound Ubuntu 24.04 LTS 1.19.2-1ubuntu1

ubuntu advisories UBUNTU-CVE-2024-1931

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • unbound Linux Micro 6.0 1.21.0-1.1

suse advisories SUSE-SU-2025:20024-1

  • unbound openSUSE Tumbleweed 1.19.2-1.1

opensuse advisories openSUSE-SU-2024:13762-1

  • unbound Alpine 3.24, Alpine 3.23, Alpine 3.22 +5 more 1.19.2-r0

alpine advisories ALPINE-CVE-2024-1931

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2024-1931 updated cvss 5.9

unbound: Infinite loop due to improper EDE message size check

  • Red Hat Enterprise Linux 6 unbound, unbound-libs, unbound-python Red Hat Enterprise Linux 7 unbound, unbound-libs, unbound-python
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 9 unbound, unbound-libs, unbound-dracut, python3-unbound
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Enterprise Linux 8 unbound, unbound-libs, python3-unbound
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
2 y ago

Exploit prediction

2.52% chance of exploitation in the next 30 days, higher than 84% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • NLnet Labs Unbound
  • nlnetlabs unbound

Classification

Weakness
  • CWE-835 Loop with Unreachable Exit Condition

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.