Application crash via unchecked SVCB parameter length
Published Jul 21, 2026 · Updated Jul 21, 2026
Out-of-bounds read in The Go Project dnsmessage before 0.56.0 allows remote attackers to crash applications via crafted SVCB or HTTPS records. The unpackSVCBResource parser trusted each parameter's declared 16-bit size during its second pass and sliced the message buffer without first confirming that the remaining bytes covered that value. Only applications that parse attacker-controlled DNS SVCB or HTTPS data through an affected symbol are exposed, and a successful trigger causes a Go runtime panic rather than data disclosure or modification.
Summary
What happened
Out-of-bounds read in The Go Project dnsmessage before 0.56.0 allows remote attackers to crash applications via crafted SVCB or HTTPS records. The unpackSVCBResource parser trusted each parameter's declared 16-bit size during its second pass and sliced the message buffer without first confirming that the remaining bytes covered that value. Only applications that parse attacker-controlled DNS SVCB or HTTPS data through an affected symbol are exposed, and a successful trigger causes a Go runtime panic rather than data disclosure or modification.
The record
- CVE
- CVE-2026-46600
- Published
- Jul 21, 2026
- Updated
- Jul 21, 2026
- Vendor
- golang.org/x/net
- Product
- golang.org/x/net/dns/dnsmessage
- Classifications
- CWE-125, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 21, 2026CVE publishedPublication date reported by the CVE source.
- Jul 21, 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=0 <0.56.0
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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