CVE-2020-25683: Buffer Overflow
First published: Wed Sep 23 2020(Updated: )
A flaw was found in dnsmasq before version 2.83. A heap-based buffer overflow was discovered in dnsmasq when DNSSEC is enabled and before it validates the received DNS entries. A remote attacker, who can create valid DNS replies, could use this flaw to cause an overflow in a heap-allocated memory. This flaw is caused by the lack of length checks in rfc1035.c:extract_name(), which could be abused to make the code execute memcpy() with a negative size in get_rdata() and cause a crash in dnsmasq, resulting in a denial of service. The highest threat from this vulnerability is to system availability.
Credit: secalert@redhat.com
| Affected Software | Affected Version | How to fix |
|---|---|---|
| redhat/dnsmasq | <2.83 | 2.83 |
| Thekelleys Dnsmasq | <2.83 | |
| Fedoraproject Fedora | =32 | |
| Fedoraproject Fedora | =33 | |
| Debian Debian Linux | =9.0 | |
| Debian Debian Linux | =10.0 | |
| debian/dnsmasq | 2.80-1+deb10u1 2.85-1 2.89-1 |
Never miss a vulnerability like this again
Sign up to SecAlerts for real-time vulnerability data matched to your software, aggregated from hundreds of sources.
Reference Links
- https://bugzilla.redhat.com/show_bug.cgi?id=1882018
- https://lists.debian.org/debian-lts-announce/2021/03/msg00027.html
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/QGB7HL3OWHTLEPSMLDGOMXQKG3KM2QME/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/WYW3IR6APUSKOYKL5FT3ACTIHWHGQY32/
- https://security.gentoo.org/glsa/202101-17
- https://www.debian.org/security/2021/dsa-4844
- https://www.jsof-tech.com/disclosures/dnspooq/
- https://www.openwall.com/lists/oss-security/2021/01/19/1
- https://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commit;h=4e96a4be685c9e4445f6ee79ad0b36b9119b502a
- https://security-tracker.debian.org/tracker/CVE-2020-25683
- https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=1917783
- https://access.redhat.com/errata/RHSA-2021:0152
- https://access.redhat.com/errata/RHSA-2021:0150
- http://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commit;h=4e96a4be685c9e4445f6ee79ad0b36b9119b502a
- https://access.redhat.com/errata/RHSA-2021:0151
- https://access.redhat.com/security/cve/cve-2020-25683
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WYW3IR6APUSKOYKL5FT3ACTIHWHGQY32/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QGB7HL3OWHTLEPSMLDGOMXQKG3KM2QME/
Frequently Asked Questions
What is CVE-2020-25683?
CVE-2020-25683 is a vulnerability found in dnsmasq before version 2.83 that allows a remote attacker to cause a heap-based buffer overflow.
How does CVE-2020-25683 affect dnsmasq?
CVE-2020-25683 affects dnsmasq when DNSSEC is enabled and before it validates the received DNS entries.
Who is affected by CVE-2020-25683?
Users of dnsmasq versions before 2.83 are affected by CVE-2020-25683.
What is the severity of CVE-2020-25683?
The severity of CVE-2020-25683 is high with a CVSS score of 5.9.
How can I mitigate CVE-2020-25683?
To mitigate CVE-2020-25683, update dnsmasq to version 2.83 or later.
- collector/nvd-index
- collector/security-tracker-debian
- agent/type
- agent/last-modified-date
- agent/softwarecombine
- agent/first-publish-date
- collector/redhat-bugzilla
- source/Red Hat
- alias/CVE-2020-25683
- agent/software-canonical-lookup
- agent/author
- agent/remedy
- agent/references
- agent/severity
- agent/weakness
- agent/tags
- agent/description
- agent/event
- collector/mitre-cve
- source/MITRE
- vendor/thekelleys
- canonical/thekelleys dnsmasq
- vendor/fedoraproject
- canonical/fedoraproject fedora
- version/fedoraproject fedora/32
- version/fedoraproject fedora/33
- vendor/debian
- canonical/debian debian linux
- version/debian debian linux/9.0
- version/debian debian linux/10.0
- package-manager/debian
- package-manager/redhat