CVE-2026-33261
MediumCVSS 5.9Exploitation Probability (EPSS)
Low risk15th percentile - higher than 15% of all known CVEs
Summary
A zone transition from NSEC to NSEC3 might trigger an internal inconsistency and cause a denial of service.
Risk Assessment
DNS service unavailability may occur due to internal inconsistency during a zone transition from NSEC to NSEC3.
Recommendation
Plan the NSEC to NSEC3 zone transition carefully and monitor DNS software updates for a fix.
Other vulnerabilities in DNS
See all- CVE-2026-6949Medium
A TSIG packet with name compression can crash DNS. Incorrect size calculations when a TSIG record contains compressed names lead to a large out-of-bounds write, causing a server crash.
- CVE-2023-50387High
The KeyTrap vulnerability in the DNSSEC protocol allows a remote attacker to cause a Denial of Service (DoS) by sending DNSSEC responses containing many DNSKEY and RRSIG records. This leads to excessive CPU consumption on the DNS server, potentially causing overload.
- CVE-2026-52684Low
A DNS issue occurs when the authoritative server responds very slowly and records expire in the meantime. In this case, TTL capping is not enforced due to lack of data. This does not happen during normal resolution.
- CVE-2026-33258Medium
In a DNS system, an attacker can publish and query a crafted zone to cause allocation of large entries in the negative and aggressive NSEC(3) caches.
- CVE-2025-59029Medium
An attacker can trigger an assertion failure by requesting crafted DNS records, waiting for them to be inserted into the records cache, then sending a query with qtype set to ANY.
- CVE-2025-2962High
A denial-of-service issue in the DNS implementation could cause an infinite loop. This may lead to a hang or unavailability of the service.
- CVE-2025-1674High
A lack of input validation allows for out-of-bounds reads caused by malicious or malformed packets. This may lead to data disclosure or a crash.
- CVE-2025-1673High
A malicious or malformed DNS packet without a payload can cause an out-of-bounds read, resulting in a crash (denial of service) or an incorrect computation. The vulnerability affects DNS packet processing.
- CVE-1999-1379Medium
The vulnerability in DNS allows remote attackers to use DNS name servers as traffic amplifiers. An attacker can send a UDP DNS query with a spoofed source address, resulting in more traffic to the victim than was sent by the attacker.
Original NVD description (English source)
A zone transition from NSEC to NSEC3 might trigger an internal inconsistency and cause a denial of service.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS

