Metrics
Affected Vendors & Products
Wed, 20 May 2026 23:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Nlnetlabs
Nlnetlabs unbound |
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| CPEs | cpe:2.3:a:nlnetlabs:unbound:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Nlnetlabs
Nlnetlabs unbound |
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| Metrics |
cvssV3_1
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Wed, 20 May 2026 14:30:00 +0000
| Type | Values Removed | Values Added |
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| Metrics |
ssvc
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Wed, 20 May 2026 10:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | 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 counter to calculate write offsets for ADDITIONAL section rrsets. DNAME duplication could increase the ANSWER section count and authority filtering could decrease the AUTHORITY section count and create an uninitialized array slot. Combining these two, the validator later dereferences this uninitialized pointer, causing an immediate process crash. An adversary controlling a DNSSEC-signed domain can trigger this bug with a single query by configuring a DNAME chain with unsigned CNAMEs and a response containing unsigned AUTHORITY records alongside signed ADDITIONAL glue records. Unbound 1.25.1 contains a patch with a fix to use the proper counters to calculate the write offsets. | |
| Title | Crash during DNSSEC validation of malicious content | |
| Weaknesses | CWE-824 | |
| References |
| |
| Metrics |
cvssV4_0
|
Status: PUBLISHED
Assigner: NLnet Labs
Published:
Updated: 2026-05-20T13:12:56.258Z
Reserved: 2026-05-07T10:07:51.848Z
Link: CVE-2026-42959
Updated: 2026-05-20T13:12:46.810Z
Status : Analyzed
Published: 2026-05-20T10:16:27.903
Modified: 2026-05-20T22:51:00.717
Link: CVE-2026-42959
No data.
OpenCVE Enrichment
Updated: 2026-05-20T11:30:26Z