Six new dnsmasq vulnerabilities open the door to DNS cache poisoning, local root
Six dnsmasq flaws enable DNS cache poisoning, DoS, memory leaks, and local root code execution; fixes ship in version 2.92rel2.
Researchers disclosed six dnsmasq vulnerabilities spanning memory safety and input validation, including heap buffer overflows in extract_name() and extract_addresses(), DNSSEC infinite-loop and out-of-bounds read flaws, and a DHCPv6 out-of-bounds write allowing local root code execution. Exploitation paths include DNS cache poisoning, bypassing security controls, remote denial of service, and local privilege escalation. Maintainers released version 2.92rel2 with fixes, and a stable 2.93 release is expected within weeks.
- CVE-2026-2291 heap overflow lets attackers poison DNS cache or cause DoS
- CVE-2026-4892 DHCPv6 write flaw grants local attackers root code execution
- CVE-2026-4890 infinite loop and CVE-2026-4891 OOB read affect DNSSEC validation
- Fixes available in 2.92rel2; stable 2.93 release planned
- Products
- dnsmasq
- Organizations
- dnsmasq project
Vulnerabilities mentioned
All| CVE | Vulnerability | CVSS | EPSS | Signals | Published |
|---|---|---|---|---|---|
| CVE-2026-2291 | dnsmasqs extract_name() function can be abused to cause a heap buffer overflow, allowing an attacker to inject false DNS cache entries, which could result in… | 7.3 | <1% | ||
| CVE-2026-4890 | A Denial of Service (DoS) vulnerability in the DNSSEC validation of dnsmasq allows remote attackers to cause a denial of service via a crafted DNS packet | 7.5 | 9% | ||
| CVE-2026-4891 | A heap-based out-of-bounds read vulnerability in the DNSSEC validation of dnsmasq allows remote attackers to cause a denial of service via a crafted DNS packet | 5.3 | 6% | ||
| CVE-2026-4892 | A heap-based out-of-bounds write vulnerability in the DHCPv6 implementation of dnsmasq allows local attackers to execute arbitrary code with root privileges… | 8.4 | <1% | ||
| CVE-2026-4893 | An information disclosure vulnerability in dnsmasq allows remote attackers to bypass source checks via a crafted DNS packet with RFC 7871 client subnet… | 5.3 | 2% | ||
| CVE-2026-5172 | A buffer overflow in dnsmasq’s extract_addresses() function allows an attacker to trigger a heap out-of-bounds read and crash by exploiting a malformed DNS… | 7.3 | 3% |
From the original article
1 min read at helpnetsecurity.com
Recent disclosures have revealed that open-source networking tool dnsmasq is grappling with a serious set of vulnerabilities. The problems span memory safety and input validation, with researchers identifying heap buffer overflows, heap corruption, and code execution bugs among the issues.
By @helpnetsecurity · helpnetsecurity.com
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