UBUNTU-CVE-2026-97043: Medium severity ubuntu/golang-1.10 vulnerability
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
What must an attacker supply or control to exploit this issue?
The attacker needs to provide a malicious package that uses cgo and contains crafted quoting in //go:cgo_ldflag directives. Exploitation occurs when that package is built.
Which Ubuntu Go packages are listed as affected?
The listed packages are ubuntu/golang-1.6, ubuntu/golang-1.8, ubuntu/golang-1.10, ubuntu/golang-1.13, ubuntu/golang-1.16, ubuntu/golang-1.18, ubuntu/golang-1.22, and ubuntu/golang-1.24.
What can happen when a vulnerable toolchain builds a crafted package?
Crafted directives can smuggle disallowed linker flags or unvalidated linker search paths past go command checks and pass them to the external linker, potentially causing code execution during the build. A crafted flag list can also cause the go command to panic due to an out-of-bounds slice index.