CVE-2020-25682
No exploitation reported by the sources we read.
- Published2021-01-20
- WeaknessCWE-122 · CWE-787
Am I affected?
Debian, Ubuntu or Red Hat sometimes backport a fix without changing the upstream version number: such a version reads « to verify », never « affected ».With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.
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.
Timeline
dates in UTC- 2021-01-2017:15CVE publishedNVD
- 2026-10-2319:23EPSS crossed 10 %FIRST EPSS
Observed activity
isMalicious corpus · updated 2026-10-23 18:48 UTCBlock these indicators
- Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2020-25682?format=txt
- CSV export: https://api.ismalicious.com/edl/cve/CVE-2020-25682?format=csv
- TAXII collection of exploited CVEs
- The EDL and CSV take an API key on the Pro plan.
Versions per branch
NVD| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 9.0 | = 9.0 | no fix published | NVD |
| 10.0 | = 10.0 | no fix published | NVD |
| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 32.x | = 32 | no fix published | NVD |
| 33.x | = 33 | no fix published | NVD |
| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 2.83 | < 2.83 | 2.83 | NVD |
as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.
Fix
Advisories and patches
- bugzilla.redhat.comPatch
Detection
- Nuclei template
- none so far ProjectDiscovery
- Exploit-DB
- no entry Exploit-DB
- Proof-of-concept repositories
- none listed PoC-in-GitHub
Sources
- NVDCVSS 3.18.1read 2026-10-23
- NVDCVSS 2.08.3read 2026-10-23
- CNAweakness (CWE)CWE-122read 2026-10-23
- NVDweakness (CWE)CWE-787read 2026-10-23
- FIRST EPSSEPSS score75.1 %read 2026-10-23
Technical details
- CVSS v3 Vector
- CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
- Published
- 2021-01-20
- Last Modified
- 2026-06-17
- NVD status
- Modified
Frequently asked questions
What is CVE-2020-25682?
Is CVE-2020-25682 actively exploited?
What is the CVSS score for CVE-2020-25682?
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