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Public proof of conceptFix available

CVE-2021-45955

A public proof of concept exists; no exploitation attested.

  • Published2022-01-01
  • WeaknessCWE-787

Am I 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

Dnsmasq 2.86 has a heap-based buffer overflow in resize_packet (called from FuzzResizePacket and fuzz_rfc1035.c) because of the lack of a proper bounds check upon pseudo header re-insertion. NOTE: the vendor's position is that CVE-2021-45951 through CVE-2021-45957 "do not represent real vulnerabilities, to the best of our knowledge." However, a contributor states that a security patch (mentioned in 016162.html) is needed

Timeline

dates in UTC
  1. 2022-01-0100:15CVE publishedNVD

Versions per branch

NVD
Thekelleys dnsmasq
BranchAffectedFixed in
2.86= 2.86no fix published

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • dnsmasqAzure Linux:2all versions · fixed in 2.89-2

Vendor advisories

  • CVE-2021-45955 Red Hat Product Security

    dnsmasq: heap-based buffer overflow in resize_packet

Full record on NVD

Fix

No fix published by the sources we read yet. NVD record

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published
2022-01-01
Last Modified
2026-06-17
NVD status
Modified
GitHub Advisory
GHSA-p5g5-mjp3-mr9m

Frequently asked questions

What is CVE-2021-45955?

Dnsmasq 2.86 has a heap-based buffer overflow in resize_packet (called from FuzzResizePacket and fuzz_rfc1035.c) because of the lack of a proper bounds check upon pseudo header re-insertion. NOTE: the vendor's position is that CVE-2021-45951 through CVE-2021-45957 "do not represent real vulnerabilities, to the best of our knowledge." However, a contributor states that a security patch (mentioned in 016162.html) is needed

Is CVE-2021-45955 actively exploited?

A proof-of-concept exploit exists for CVE-2021-45955, but active exploitation has not been confirmed at this time.

What is the CVSS score for CVE-2021-45955?

CVE-2021-45955 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

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Sources for this record