CVE-2020-25682
A buffer overflow vulnerability was discovered in the way dnsmasq extract names from DNS packets before validating them with DNSSEC data.
Does this matter?
EPSS puts the probability of exploitation in the next 30 days at 75.1%, higher than 100% of all known CVEs. Patch or mitigate before the next change window.
Description
A flaw was found in dnsmasq before 2.83. A buffer overflow vulnerability was discovered in the way dnsmasq extract names from DNS packets before validating them with DNSSEC data. An attacker on the network, who can create valid DNS replies, could use this flaw to cause an overflow with arbitrary data in a heap-allocated memory, possibly executing code on the machine. The flaw is in the rfc1035.c:extract_name() function, which writes data to the memory pointed by name assuming MAXDNAME*2 bytes are available in the buffer. However, in some code execution paths, it is possible extract_name() gets passed an offset from the base buffer, thus reducing, in practice, the number of available bytes that can be written in the buffer. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.
- CVSS 3.1
- 8.1 HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 75.07% probability · 100th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-122, CWE-787
- Affected
- thekelleys/dnsmasq · fedoraproject/fedora · debian/debian linux
- Source
- secalert@redhat.com
EPSS moved from 75.1% on 22 October 2026 to 75.1% on 3 November 2026. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”.
References
- https://bugzilla.redhat.com/show_bug.cgi?id=1882014Issue Tracking, Patch, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2021/03/msg00027.htmlMailing List, Third Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QGB7HL3OWHTLEPSMLDGOMXQKG3KM2QME/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WYW3IR6APUSKOYKL5FT3ACTIHWHGQY32/
- https://security.gentoo.org/glsa/202101-17Third Party Advisory
- https://www.debian.org/security/2021/dsa-4844Third Party Advisory
- https://www.jsof-tech.com/disclosures/dnspooq/Third Party Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=1882014Issue Tracking, Patch, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2021/03/msg00027.htmlMailing List, Third Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QGB7HL3OWHTLEPSMLDGOMXQKG3KM2QME/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WYW3IR6APUSKOYKL5FT3ACTIHWHGQY32/
- https://security.gentoo.org/glsa/202101-17Third Party Advisory
- https://www.debian.org/security/2021/dsa-4844Third Party Advisory
- https://www.jsof-tech.com/disclosures/dnspooq/Third Party Advisory
- https://www.kb.cert.org/vuls/id/434904
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.