Service interruption via SVCB response out-of-bounds read
Published Apr 22, 2026 · Updated Apr 22, 2026
Out-of-bounds read in PowerDNS DNSdist 1.9.0 through 1.9.12 and 2.0.0 through 2.0.3 allows attackers to interrupt service via crafted SVCB responses. DDR handling assumes an SVCB answer contains a usable address and reads beyond valid response data when a backend returns none. Exploitation requires a backend under attacker control and non-default DDR auto-upgrade configuration; the reported consequence is availability loss only.
Summary
What happened
Out-of-bounds read in PowerDNS DNSdist 1.9.0 through 1.9.12 and 2.0.0 through 2.0.3 allows attackers to interrupt service via crafted SVCB responses. DDR handling assumes an SVCB answer contains a usable address and reads beyond valid response data when a backend returns none. Exploitation requires a backend under attacker control and non-default DDR auto-upgrade configuration; the reported consequence is availability loss only.
The record
- CVE
- CVE-2026-33599
- Published
- Apr 22, 2026
- Updated
- Apr 22, 2026
- Vendor
- PowerDNS
- Product
- DNSdist
- Classifications
- CWE-125, T1499
- Attack vector
- adjacent
- Privileges
- unauthenticated
Timeline
How it unfolded
- Apr 22, 2026CVE publishedPublication date reported by the CVE source.
- Apr 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?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=1.9.0 <1.9.13
- Affected versionversion=2.0.0 <2.0.4
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
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Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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