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CVE-2021-3448

18
FAUCET Score

CVE-2021-3448 is a DNS cache poisoning vulnerability affecting dnsmasq versions prior to 2.85, impacting products from vendors like Fedora, Oracle, and Red Hat. The flaw stems from dnsmasq using a fixed port for forwarding queries when configured for specific network interfaces, significantly simplifying an attacker's ability to forge DNS replies. This vulnerability has a medium severity CVSS score of 4.0, indicating a network-based attack with high complexity but a low impact on data integrity. There is no evidence of active exploitation, public exploit code, or significant community discussion surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
< 2.85CPE matchmatch criteria
cpe:2.3:a:thekelleys:dnsmasq:*:*:*:*:*:*:*:*
8.0CPE matchmatch criteria
cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
32CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*
33CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
34CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

4.0MEDIUM

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N

Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality Impact
NONE
Integrity Impact
LOW
Availability Impact
NONE
Exploitability Score
2.2
Impact Score
1.4
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.99%
Probability of exploitation in next 30 days
EPSS Percentile
78.5%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0199 is in the 63rd percentile among its peer group of 19,958 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.0 Bluesky, 0.0 Mastodon, and 0.2 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.0 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (7)

microsoftpatch availablevia msrc
Product: CBL Mariner 1.0 x64Fixed in: 2.85-1
microsoftpatch availablevia msrc
Product: CBL Mariner 1.0 ARMFixed in: 2.85-1
microsoftpatch availablevia msrc
Product: 19065-16820Fixed in: 2.85-1
microsoftpatch availablevia msrc
Product: cm1 dnsmasq 2.85-1 on CBL Mariner 1.0Fixed in: 2.85-1
oraclepatch availablevia nvd_reference
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: dnsmasq-0:2.79-19.el8
View patch
redhatpatch availablevia nvd_reference
View patch

Vendor Advisories (3)

microsoft2023-Mar/CVE-2021-3448

CVE-2021-3448

Mar 14, 2023
microsoft2021-Apr/CVE-2021-3448Moderate

A flaw was found in dnsmasq in versions before 2.85. When configured to use a specific server for a given network interface dnsmasq uses a fixed port while forwarding queries. An attacker on the network able to find the outgoing port used by dnsmasq only needs to guess the random transmission ID to forge a reply and get it accepted by dnsmasq. This flaw makes a DNS Cache Poisoning attack much easier. The highest threat from this vulnerability is to data integrity.

Apr 13, 2021
redhatCVE-2021-3448Moderate

dnsmasq: fixed outgoing port used when --server is used with an interface name

Mar 12, 2021

References

bugzilla.redhat.com / show_bug.cgi
ExploitIssue TrackingPatchThird Party Advisory
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/CVTJUOFFFHINLKWAOC2ZSC5MOPD4SJ24
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/FHG7GWSQWKF7JXIMLOGJBKZWBB4VIAJ7
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/GHURNEHHUBSW45KMIZ4FNBCSUPWPGV5V
security.gentoo.org / glsa/202105-20
Third Party Advisory
oracle.com / security-alerts/cpujan2022.html
PatchThird Party Advisory