# CVE-2026-46600: Google Go x/net denial of service in dnsmessage parsing

Source: https://junglewise.ai/threats/cve-2026-46600-google-go-x-net-denial-of-service-in-dnsmessage-parsing  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-21. Updated: 2026-07-21  
License: CC BY 4.0 with a link back

CVE-2026-46600 · Severity: info · Published 2026-07-21

A vulnerability in a common Go networking library could allow an attacker to crash applications that process DNS records. By sending a specially crafted, invalid DNS response (specifically SVCB or HTTPS records), an attacker can trigger a system 'panic' or crash. This results in a denial-of-service, potentially taking down web servers or other services that rely on this library to resolve internet addresses.

Technologies: [golang.org/x/net (Go)](https://junglewise.ai/threats/technologies/golang-org-x-net), [stdlib (Go)](https://junglewise.ai/threats/technologies/go-stdlib). Vendors: [Go](https://junglewise.ai/threats/vendors/go), [Google](https://junglewise.ai/threats/vendors/google).

## Quick answers

**Is CVE-2026-46600 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-46600 being exploited in the wild.

**How severe is CVE-2026-46600?** Informational severity, published 21 July 2026.

**Which products and versions are affected?** golang.org/x/net (Go) SEMVER:introduced=0,fixed=0.56.0; stdlib (Go) SEMVER:introduced=1.26.0-0,fixed=1.26.6,introduced=1.27.0-0,fixed=1.27.0-rc.3; Google Dnsmessage < 0.56.0.

**Is there a fix for CVE-2026-46600?** Yes. golang.org/x/net (Go): upgrade to 0.56.0 or later; stdlib (Go): upgrade to 1.27.0-rc.3 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-46600 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-46600?** Check whether you run golang.org/x/net (Go), stdlib (Go) or Google Dnsmessage at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- golang.org/x/net (Go): upgrade to 0.56.0 or later

  ```sh
  go get golang.org/x/net@v0.56.0
  ```

- stdlib (Go): upgrade to 1.27.0-rc.3 or later

  ```sh
  go get stdlib@v1.27.0-rc.3
  ```


## Technical details

A vulnerability exists in the golang.org/x/net/dns/dnsmessage package where parsing an invalid SVCB or HTTPS Resource Record (RR) can trigger a panic. The root cause is an integer overflow or bounds check failure that occurs when the size of a parameter value within the record exceeds the remaining message buffer during unpacking. This can be exploited by a remote attacker providing a malformed DNS response to an application using affected functions such as Message.Unpack or Parser.SVCBResource. The issue is fixed in version 0.56.0 of the golang.org/x/net library.

## Affected products

- Google golang.org/x/net/dns/dnsmessage < 0.56.0

## Identifiers

- CVE-2026-46600
- GO-2026-5942

## Timeline

- 2026-06-02: disclosed: Issue reported to Go project
- 2026-07-14: advisory: Go vulnerability report GO-2026-5942 published
- 2026-07-21: disclosed: CVE-2026-46600 published

## References

- [https://pkg.go.dev/](https://pkg.go.dev/)
- [https://go.dev/cl/786345](https://go.dev/cl/786345)
- [https://go.dev/issue/79795](https://go.dev/issue/79795)
- [https://pkg.go.dev/vuln/GO-2026-5942](https://pkg.go.dev/vuln/GO-2026-5942)

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