🛡️ CVE-2023-31137 on Debian — maradns

⚪ Unknown ✅ No Known Exploit OSV
N/A
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

MaraDNS is open-source software that implements the Domain Name System (DNS). In version 3.5.0024 and prior, a remotely exploitable integer underflow vulnerability in the DNS packet decompression function allows an attacker to cause a Denial of Service by triggering an abnormal program termination. The vulnerability exists in the decomp_get_rddata function within the Decompress.c file. When handling a DNS packet with an Answer RR of qtype 16 (TXT record) and any qclass, if the rdlength is smaller than rdata, the result of the line Decompress.c:886 is a negative number len = rdlength - total;. This value is then passed to the decomp_append_bytes function without proper validation, causing the program to attempt to allocate a massive chunk of memory that is impossible to allocate. Consequently, the program exits with an error code of 64, causing a Denial of Service. One proposed fix for this vulnerability is to patch Decompress.c:887 by breaking if(len <= 0), which has been incorporated in version 3.5.0036 via commit bab062bde40b2ae8a91eecd522e84d8b993bab58.

Distribution advisory

This page covers CVE-2023-31137 as tracked by Debian, for the package maradns. The fix is available in version 2.0.13-1.4+deb11u1; earlier versions remain affected.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity none, availability high.

Weakness class

DEBIAN-CVE-2023-31137 is classified as CWE-191: Integer Underflow. A subtraction drops below the minimum for the type and wraps, yielding an unexpectedly large value.

Affected software

DEBIAN-CVE-2023-31137 is recorded against 1 package.

  • maradns (fixed in 2.0.13-1.4+deb11u1)

Timeline and source

Published on 9 May 2023 and last revised on 7 August 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

security-tracker.debian.org (Advisory)

CVE-2023-31137 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity Unknown
CVSS Score N/A
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE N/A
Public Exploit ✅ No
Source OSV
Published 2023-05-09
Updated 2026-08-11
Modified 2026-08-07
Fix URL N/A

Affected Packages

Software From version Fixed in
maradns — 2.0.13-1.4+deb11u1

Similar Threats

Site Security Check

Is maradns part of your stack?

DEBIAN-CVE-2023-31137 is rated CVSS 7.5 High. BotEraser scans your installation against known CVE records and tells you whether this vulnerability applies to the versions you actually run.

Scan My Site Free →

No credit card required  ·  Results in minutes

ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

Browse related advisories

All advisoriesDebianDebian 2023