Is CVE-2026-97035 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-97035 being exploited in the wild.

How severe is CVE-2026-97035?

Informational severity, published 11 November 2026.

Which products and versions are affected?

toolchain (Go) SEMVER:introduced=0,fixed=1.26.11,introduced=1.27.0-0,fixed=1.27.4.

Is there a fix for CVE-2026-97035?

Yes. toolchain (Go): upgrade to 1.27.4 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-97035 attacked?

It is attacked with local access.

Am I affected by CVE-2026-97035?

Check whether you run toolchain (Go) or Google Go 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.

CVE-2026-97035: Go cgo arbitrary code execution via compiler flags

CVE-2026-97035 · Severity: info · Published 2026-11-11

Go's build system allows developers to specify custom C compiler flags in cgo directives, which are used when compiling packages that integrate C code. A malicious package could exploit improper validation of compiler flags (specifically "-gen-*" or "-gnat*" options) to execute arbitrary code at build time or write files to any directory on the system, affecting any project that builds untrusted Go packages.

Technologies: toolchain (Go), Google Go. Vendors: Go, Google.

Quick answers

Is CVE-2026-97035 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-97035 being exploited in the wild.
How severe is CVE-2026-97035?: Informational severity, published 11 November 2026.
Which products and versions are affected?: toolchain (Go) SEMVER:introduced=0,fixed=1.26.11,introduced=1.27.0-0,fixed=1.27.4.
Is there a fix for CVE-2026-97035?: Yes. toolchain (Go): upgrade to 1.27.4 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-97035 attacked?: It is attacked with local access.
Am I affected by CVE-2026-97035?: Check whether you run toolchain (Go) or Google Go 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

toolchain (Go): upgrade to 1.27.4 or later
```
go get toolchain@v1.27.4
```

Technical details

The Go command's flag allowlist used a "-g*" wildcard that unintentionally matched Clang's two-argument "-gen-cdb-fragment-path" and GCC's "-gnatO" flags, allowing malicious cgo directives to write files to arbitrary locations and desynchronize flag parsing, passing unvalidated arguments to the linker. The vulnerability is triggered when building a package with malicious "#cgo" compiler or linker flags. Go has patched this by explicitly disallowing "-gen-*" and "-gnat*" flags in cgo directives.

Affected products

Google Go

Identifiers

CVE-2026-97035
GO-2026-6856

Timeline

2026-11-11: disclosed

References

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