CVE-2020-25686: arista eos
Vulnerability summary
CVE-2020-25686 is a medium (CVSS 4.3) vulnerability in arista eos. EPSS estimates a 4.87% chance of exploitation in the next 30 days, higher than 91.9% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 22 · Related 9Timeline
- 20-01-2021PublishedVulnerability first disclosed.
- 04-11-2025Last modifiedVulnerability information updated.
Description
A flaw was found in dnsmasq before version 2.83. When receiving a query, dnsmasq does not check for an existing pending request for the same name and forwards a new request. By default, a maximum of 150 pending queries can be sent to upstream servers, so there can be at most 150 queries for the same name. This flaw allows an off-path attacker on the network to substantially reduce the number of attempts that it would have to perform to forge a reply and have it accepted by dnsmasq. This issue is mentioned in the "Birthday Attacks" section of RFC5452. If chained with CVE-2020-25684, the attack complexity of a successful attack is reduced. The highest threat from this vulnerability is to data integrity.
CVSS metrics
5 scores · 4 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated3.7LowCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
- OSV · DebianEcosystem advisory · calculated3.7LowCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
- NVDNIST3.7LowCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
EPSS trend
Probability
4.87%
Chance of exploitation in the next 30 days
Percentile
92%
Versus all other CVEs
30-day change
0.00 pp
From 4.87% on 18-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root cause- CWE-358Improperly Implemented Security Check for StandardThe product does not implement or incorrectly implements one or more security-relevant checks as specified by the design of a standardized algorithm, protocol, or technique.
- CWE-290Authentication Bypass by SpoofingThis attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks.
Affected systems
Debian2 products
- dnsmasq< 2.83-1
- debian_linuxEOL10.0
Alpine1 product
- dnsmasq< 2.83-r0
Arista1 product
- eos≥ 4.21, < 4.21.14m | ≥ 4.22, < 4.22.9m | ≥ 4.23, < 4.23.7m | ≥ 4.24, < 4.24.5m | ≥ 4.25, < 4.25.2f
Fedoraproject1 product
- fedoraEOL32 | 33
Thekelleys1 product
- dnsmasq< 2.83
Ubuntu1 product
- dnsmasqAll versions (No fix recorded) | < 2.75-1ubuntu0.16.04.7 | < 2.79-1ubuntu0.2 | < 2.80-1.1ubuntu1.2
6 vendors · 7 products
References
15 links
- www.arista.com/en/support/advisories-notices/security-advisories/12135-security-advisory-61X Refsource MISCThird Party Advisory
