Summary
The unbound packages provide a validating, recursive, and caching DNS or DNSSEC resolver.
Security Fix(es):
* unbound: Heap overflow and crash with multiple nsid, cookie, padding EDNS options (CVE-2026-42944)
* unbound: Unbound DNSSEC Validator Denial of Service via Incorrect Write Offset Counter in Chase-Reply Messages (CVE-2026-42959)
* unbound: Unbound DNSSEC Validator Use-After-Free via Deep Copy Pointer Overwrite Leading to DoS and Possible Remote Code Execution (CVE-2026-33278)
For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.
Fixed packages 1
| Release | Package | Fixed in |
|---|---|---|
| Rocky Linux · 10 | unbound | 0:1.24.2-7.el10_2.1 |
Vulnerabilities 3
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Critical 9.1
Possible arbitrary code execution during DNSSEC validation
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 p…
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High 8.7
Heap overflow with multiple NSID, COOKIE, PADDING EDNS options
NLnet Labs Unbound 1.14.0 up to and including version 1.25.0 has a vulnerability that results in heap overflow when encoding multiple NSID and/or DNS Cookie EDNS and/or EDNS Padding options in the reply packet. The relevant options ('nsid', 'answer-cookie', '…
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High 8.7
Crash during DNSSEC validation of malicious content
NLnet Labs Unbound up to and including version 1.25.0 has a denial of service vulnerability in the DNSSEC validator that can lead to a crash given malicious upstream replies. When Unbound constructs chase-reply messages for validation, the code uses the wrong…