AZL-113420: CVE-2026-97043 affecting package golang 1.26.11-1
Building a malicious package that uses cgo could bypass "#cgo LDFLAGS" validation and cause unexpected code execution at build time, or cause the go command to panic, via crafted quoting in "//go:cgoldflag" directives. When "cmd/cgo" generates "cgogotypes.go", it quotes each "#cgo LDFLAGS" argument with strconv.Quote in a "//go:cgoldflag" directive, but "cmd/compile" and "cmd/go" parsed those directives by splitting on raw quote characters without handling backslash escapes or unquoting the string. This mismatch allowed disallowed linker flags or unvalidated linker search paths to be smuggled past the go command's flag checks and passed to the external linker. In addition, deduplicating LDFLAGS in the go command could panic with an out-of-bounds slice index when a prefix of the flag list matched near the end of the slice. "cmd/compile" and "cmd/go" now properly handle backslash-escaped quotes and unquote "//go:cgo" pragma strings with strconv.Unquote, and the slice bounds check in processCgoOutputs has been fixed.
Affected Software
Event History
Frequently Asked Questions
Who is exposed to this issue?
Build environments that compile untrusted or malicious Go packages using cgo are exposed. The impact occurs during the build process, where crafted directives can cause unexpected code execution or make the go command panic.
What does an attacker need to exploit it?
An attacker needs to provide a Go package that uses cgo and contains crafted quoting in //go:cgo_ldflag directives. The package must then be built by the affected Go toolchain.
Can this bypass Go's linker-flag protections?
Yes. Crafted quoting could smuggle disallowed linker flags or unvalidated linker search paths past the go command's flag validation and pass them to the external linker.
What can be done before updating the toolchain?
Avoid building untrusted Go packages that use cgo, particularly in sensitive or automated build environments. Treat cgo-enabled dependencies and source inputs as trusted until the corrected toolchain is deployed.
How can I tell whether a build may have been affected?
Review builds of untrusted cgo packages for crafted //go:cgo_ldflag directives and unusual quoting in linker-flag inputs. Affected builds may also have failed with a go command panic during LDFLAGS deduplication.