Daemon crash via freed DoT server name
Published Jul 22, 2026 · Updated Jul 22, 2026
Use-after-free in NLnet Labs Unbound 1.15.0 through 1.25.1 allows remote attackers to crash the resolver via forwarded DoT queries. The waiting_tcp structure retains a TLS server-name pointer owned by serviced_query, which frees the string when mesh pressure jostles the query before the handshake completes. Exploitation requires a DoT stub or forward zone with an #authname suffix, precise jostling, and a transient TLS failure; the resulting read dereference terminates the daemon.
Summary
What happened
Use-after-free in NLnet Labs Unbound 1.15.0 through 1.25.1 allows remote attackers to crash the resolver via forwarded DoT queries. The waiting_tcp structure retains a TLS server-name pointer owned by serviced_query, which frees the string when mesh pressure jostles the query before the handshake completes. Exploitation requires a DoT stub or forward zone with an #authname suffix, precise jostling, and a transient TLS failure; the resulting read dereference terminates the daemon.
The record
- CVE
- CVE-2026-50046
- Published
- Jul 22, 2026
- Updated
- Jul 22, 2026
- Vendor
- NLnet Labs
- Product
- Unbound
- Classifications
- CWE-416, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 22, 2026CVE publishedPublication date reported by the CVE source.
- Jul 22, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=1.15.0 <1.25.2
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Public exploit references
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Technologies
Your stack
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Your stack
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