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TI-2020-15698 Aliases CVE-2020-25682GHSA-3qqq-357h-32gj

Heap-based buffer overflow in dnsmasq

Priority HIGH 74CWE-122Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
High
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-122 and the CVSS impact.

Summary

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.

Why it matters now

EPSS 0.75066 99th percentileScored 2026-11-07
Fix Fixed Red Hat: 3 advisories

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
—dnsmasqdnsmasq 2.83—No fix listedCNA
  • dnsmasq Vendor— Affected dnsmasq 2.83 Fixed in — No fix listed CNA

CPE configurations NVD · 5

CPEVersionsRoleVendor
cpe:2.3:a:thekelleys:dnsmasq:*:*:*:*:*:*:*:*before 2.83VulnerableThekelleys
cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*32VulnerableFedoraproject
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*33VulnerableFedoraproject
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*9.0VulnerableDebian
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*10.0VulnerableDebian
  • cpe:2.3:a:thekelleys:dnsmasq:*:*:*:*:*:*:*:* Versions before 2.83 Vulnerable ·Thekelleys
  • cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:* Versions 32 Vulnerable ·Fedoraproject
  • cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:* Versions 33 Vulnerable ·Fedoraproject
  • cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:* Versions 9.0 Vulnerable ·Debian
  • cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:* Versions 10.0 Vulnerable ·Debian

Remediation

Red Hat 3 advisories

  • RHSA-2021:0150 Released 2021-01-19 · Red Hat rating Important
    dnsmasq security update
    • Red Hat Enterprise Linux AppStream (v. 8) dnsmasq-2.79-13.el8_3.1, dnsmasq-utils-2.79-13.el8_3.1
  • RHSA-2021:0151 Released 2021-01-19 · Red Hat rating Important
    dnsmasq security update
    • Red Hat Enterprise Linux AppStream EUS (v. 8.2) dnsmasq-2.79-11.el8_2.2, dnsmasq-utils-2.79-11.el8_2.2
  • RHSA-2021:0152 Released 2021-01-19 · Red Hat rating Important
    dnsmasq security update
    • Red Hat Enterprise Linux AppStream EUS (v. 8.1) dnsmasq-2.79-6.el8_1.1, dnsmasq-utils-2.79-6.el8_1.1

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Advisory ·

    dnsmasq — FEDORA-2021-2e4c3d5a9d

    7 records Highest priority Priority HIGH 4 HIGH, 3 LOW

    Other records, highest priority first

    • TI-2020-15697 Heap-based buffer overflow in dnsmasqPriority HIGH 76
    • TI-2020-15703 Heap-based buffer overflow in dnsmasqPriority HIGH 69
    • TI-2020-15699 Heap-based buffer overflow in dnsmasqPriority HIGH 69
    Show all 7 records → Advisory →
  • Advisory ·

    dnsmasq — FEDORA-2021-84440e87ba

    7 records Highest priority Priority HIGH 4 HIGH, 3 LOW

    Other records, highest priority first

    • TI-2020-15697 Heap-based buffer overflow in dnsmasqPriority HIGH 76
    • TI-2020-15703 Heap-based buffer overflow in dnsmasqPriority HIGH 69
    • TI-2020-15699 Heap-based buffer overflow in dnsmasqPriority HIGH 69
    Show all 7 records → Advisory →
Show 2 more groups
  • Advisory ·

    dnsmasq — GLSA-202101-17

    7 records Highest priority Priority HIGH 4 HIGH, 3 LOW

    Other records, highest priority first

    • TI-2020-15697 Heap-based buffer overflow in dnsmasqPriority HIGH 76
    • TI-2020-15703 Heap-based buffer overflow in dnsmasqPriority HIGH 69
    • TI-2020-15699 Heap-based buffer overflow in dnsmasqPriority HIGH 69
    Show all 7 records → Advisory →
  • Advisory ·

    dnsmasq — DSA-4844

    7 records Highest priority Priority HIGH 4 HIGH, 3 LOW

    Other records, highest priority first

    • TI-2020-15697 Heap-based buffer overflow in dnsmasqPriority HIGH 76
    • TI-2020-15703 Heap-based buffer overflow in dnsmasqPriority HIGH 69
    • TI-2020-15699 Heap-based buffer overflow in dnsmasqPriority HIGH 69
    Show all 7 records → Advisory →

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux AppStream (v. 8)Fixed RHSA-2021:0150
Red Hat Enterprise Linux AppStream EUS (v. 8.1)Fixed RHSA-2021:0152
Red Hat Enterprise Linux AppStream EUS (v. 8.2)Fixed RHSA-2021:0151
Not affected: 6 products
  • Red Hat Enterprise Linux 5
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 7
  • Red Hat Enterprise Linux 9
  • Red Hat OpenStack Platform 10 (Newton)
  • Red Hat OpenStack Platform 13 (Queens)

Timeline

  1. 2026-10-02 Threatist record created from CVE-2020-25682
  2. 2026-10-03 Alias added: GHSA-3qqq-357h-32gj

References

Patch 1

Advisory 6

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences