Vulnerability 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 Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Thekelleys | Dnsmasq | < 2.83 |
| Fedoraproject | Fedora | 32 |
| Debian | Debian Linux | 9.0 |
Related Weaknesses (CWE)
References
- https://bugzilla.redhat.com/show_bug.cgi?id=1882014Issue TrackingPatchThird Party Advisory
- https://lists.debian.org/debian-lts-announce/2021/03/msg00027.htmlMailing ListThird Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
- 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 TrackingPatchThird Party Advisory
- https://lists.debian.org/debian-lts-announce/2021/03/msg00027.htmlMailing ListThird Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
- 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
FAQ
What is CVE-2020-25682?
CVE-2020-25682 is a vulnerability with a CVSS score of 8.1 (HIGH). 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 ne...
How severe is CVE-2020-25682?
CVE-2020-25682 has been rated HIGH with a CVSS base score of 8.1/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2020-25682?
Check the references section above for vendor advisories and patch information. Affected products include: Thekelleys Dnsmasq, Fedoraproject Fedora, Debian Debian Linux.