CVE-2026-33278— Possible arbitrary code execution during DNSSEC validation
Possible ATT&CK Techniques 1AI
T1190 · Exploit Public-Facing ApplicationAffected Version Matrix 1
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| NLnet Labs | Unbound | 1.19.1< 1.25.1 | affected |
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I. Basic Information for CVE-2026-33278
Vulnerability Information
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Vulnerability Title
Possible arbitrary code execution during DNSSEC validation
Source: NVD (National Vulnerability Database)
Vulnerability Description
NLnet Labs Unbound 1.19.1 up to and including version 1.25.0 has a vulnerability in the DNSSEC validator that enables denial of service and possible remote code execution as a result of deep copying a data structure and erroneously overwriting a destination pointer. An adversary can exploit the vulnerability by controlling a malicious signed zone and querying a vulnerable Unbound. When DS sub-queries need to suspend validation due to NSEC3 computational budget exhaustion (introduced in Unbound 1.19.1), Unbound deep-copies response messages to preserve them across memory region teardown. A struct-assignment bug overwrites the destination's pointer with the source's pointer. After the sub-query region is freed, the resumed validator dereferences this dangling pointer, triggering a crash or potentially enabling arbitrary code execution. Unbound 1.25.1 contains a patch with a fix to preserve the correct pointer when deep copying the data structure.
Source: NVD (National Vulnerability Database)
CVSS Information
N/A
Source: NVD (National Vulnerability Database)
Vulnerability Type
释放后使用
Source: NVD (National Vulnerability Database)
Affected Products
| Vendor | Product | Affected Versions | CPE | Subscribe |
|---|---|---|---|---|
| NLnet Labs | Unbound | 1.19.1 ~ 1.25.1 | - |
II. Public POCs for CVE-2026-33278
| # | POC Description | Source Link | Shenlong Link |
|---|
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Same Patch Batch · NLnet Labs · 2026-05-20 · 11 CVEs total
| CVE-2026-41292 | Long list of incoming EDNS options degrades performance | |
| CVE-2026-42959 | Crash during DNSSEC validation of malicious content | |
| CVE-2026-42923 | Degradation of service with unbounded NSEC3 hash calculations | |
| CVE-2026-42944 | Heap overflow with multiple NSID, COOKIE, PADDING EDNS options | |
| CVE-2026-42960 | Possible cache poisoning via promiscuous records for the authority section | |
| CVE-2026-42534 | Jostle logic bypass degrades resolution performance | |
| CVE-2026-32792 | Packet of death with DNSCrypt | |
| CVE-2026-40622 | Another 'ghost domain names' attack variant | |
| CVE-2026-44390 | Unbounded name compression in certain cases causes degradation of service | |
| CVE-2026-44608 | Use after free and crash under special conditions in RPZ code |
IV. Related Vulnerabilities
Same product: Unbound
- CVE-2026-44608
Use after free and crash under special conditions in RPZ cod - CVE-2026-44390
Unbounded name compression in certain cases causes degradati - CVE-2026-42960
Possible cache poisoning via promiscuous records for the aut - CVE-2026-42959
Crash during DNSSEC validation of malicious content - CVE-2026-42944
Heap overflow with multiple NSID, COOKIE, PADDING EDNS optio
Same vendor: NLnet Labs
- CVE-2026-44608
Use after free and crash under special conditions in RPZ cod - CVE-2026-44390
Unbounded name compression in certain cases causes degradati - CVE-2026-42960
Possible cache poisoning via promiscuous records for the aut - CVE-2026-42959
Crash during DNSSEC validation of malicious content - CVE-2026-42944
Heap overflow with multiple NSID, COOKIE, PADDING EDNS optio
V. Comments for CVE-2026-33278
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