CVE-2026-97040 Cgo directive injection via .syso files disguised as Go object files in cmd/go and cmd/link
go toolchain: no CVSS score yet. EPSS 0.2% estimated probability of exploitation activity in the next 30 days. Fixed in toolchain 1.26.11, 1.27.4.
On this page
Building a package containing a crafted ".syso" file could bypass cgo flag validation and inject arbitrary linker flags when linking. When loading ".syso" entries from a package archive, the linker only checked for recognized host object headers (ELF, Mach-O, PE, and XCOFF) before falling through to Go object parsing. A ".syso" file beginning with a "go object" header was parsed as a Go compiler object, allowing untrusted cgo metadata directives (such as "cgo_ldflag" or "cgo_dynamic_linker") embedded in the ".syso" file to be passed to the external linker without validation. Additionally, ".syso" filenames longer than 16 bytes lost their ".syso" extension when truncated in archive headers, and unrecognized ".syso" formats forced external linking in pure-Go builds. The linker now rejects ".syso" files that are not recognized host object formats, and "cmd/go" and "cmd/pack" preserve the ".syso" suffix when truncating long archive member names.
- EPSS
- 0.2% estimated probability of exploitation activity in the next 30 days; 16th percentile. Scored 2026-11-13. A forecast for this CVE across the internet, not for your own systems.
- Published
- Modified
- Assigned by
- Go (CNA)
- NVD analysis
- Awaiting analysis
- Record from
- the NVD, synced
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Affected
- go toolchain:cmd/go
- go toolchain:cmd/link
Versions
From the CNA's record in the CVE List.
| Product | Affected |
|---|---|
| Go toolchain cmd/go | before 1.26.11 |
| Go toolchain cmd/go | from 1.27.0-0 before 1.27.4 |
| Go toolchain cmd/link | before 1.26.11 |
| Go toolchain cmd/link | from 1.27.0-0 before 1.27.4 |
Fix and patched versions
toolchain(Go): fixed in 1.26.11, 1.27.4- Debian, SUSE, openSUSE, Alpine: fixed package versions per release
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GO-2026-6851 | Go | toolchain | <1.26.11 >=1.27.0-0 <1.27.4 | 1.26.11, 1.27.4 |
Linux distributions
| Distribution | Release | Package | Fixed in | Advisory |
|---|---|---|---|---|
| Debian | 12 | golang-1.19 | no fix listed | DEBIAN-CVE-2026-97040 |
| Debian | 13 | golang-1.24 | no fix listed | DEBIAN-CVE-2026-97040 |
| Debian | 14 | golang-1.26 | 1.26.11-1 | DEBIAN-CVE-2026-97040 |
| Debian | 14 | golang-1.27 | 1.27.4-1 | DEBIAN-CVE-2026-97040 |
| Ubuntu | 14.04:LTS | golang-1.10 | no fix listed | UBUNTU-CVE-2026-97040 |
| Ubuntu | 16.04:LTS | golang-1.6, golang-1.10 | no fix listed | UBUNTU-CVE-2026-97040 |
| Ubuntu | 18.04:LTS | golang-1.8, golang-1.9, golang-1.10 | no fix listed | UBUNTU-CVE-2026-97040 |
| Ubuntu | 20.04:LTS | golang-1.13, golang-1.14, golang-1.18 and 3 more | no fix listed | UBUNTU-CVE-2026-97040 |
| Ubuntu | 22.04:LTS | golang-1.17, golang-1.18, golang-1.20 and 6 more | no fix listed | UBUNTU-CVE-2026-97040 |
| Ubuntu | 24.04:LTS | golang-1.21, golang-1.22, golang-1.23 and 3 more | no fix listed | UBUNTU-CVE-2026-97040 |
| Ubuntu | 26.04:LTS | golang-1.23, golang-1.24, golang-1.25 and 1 more | no fix listed | UBUNTU-CVE-2026-97040 |
| Ubuntu | 26.10 | golang-1.26, golang-1.27 | no fix listed | UBUNTU-CVE-2026-97040 |
| Ubuntu | Pro:16.04:LTS | golang-1.13, golang-1.18 | no fix listed | UBUNTU-CVE-2026-97040 |
| Ubuntu | Pro:18.04:LTS | golang-1.13, golang-1.16, golang-1.18 | no fix listed | UBUNTU-CVE-2026-97040 |
| Ubuntu | Pro:20.04:LTS | golang-1.16 | no fix listed | UBUNTU-CVE-2026-97040 |
| Ubuntu | Pro:22.04:LTS | golang-1.13 | no fix listed | UBUNTU-CVE-2026-97040 |
| SUSE | Linux Enterprise High Performance Computing 15 SP4-ESPOS, Linux Enterprise High Performance Computing 15 SP4-LTSS, Linux Enterprise High Performance Computing 15 SP5-ESPOS and 8 more | go1.26 | 1.26.11-150000.1.39.1 | SUSE-SU-2026:5227-1 |
| SUSE | Linux Enterprise High Performance Computing 15 SP4-ESPOS, Linux Enterprise High Performance Computing 15 SP4-LTSS, Linux Enterprise High Performance Computing 15 SP5-ESPOS and 8 more | go1.27 | 1.27.4-150000.1.18.1 | SUSE-SU-2026:5226-1 |
| openSUSE | Tumbleweed | go1.26 | 1.26.11-1.1 | openSUSE-SU-2026:12529-1 |
| Alpine | v3.24 | go | 1.26.11-r0 | ALPINE-CVE-2026-97040 |
| Azure Linux | 3 | gcc | no fix listed | AZL-113414 |
| Azure Linux | 3 | golang | no fix listed | AZL-113441 AZL-113477 |
| Azure Linux | 3 | python-tensorboard | no fix listed | AZL-113576 |
| Azure Linux | 3 | tensorflow | no fix listed | AZL-113645 |
From the distributions' data via OSV.dev: the Debian Security Tracker; Ubuntu Security Notices © Canonical Ltd., CC BY-SA 4.0; SUSE security data, CC BY 4.0; the Alpine secdb, CC BY-SA 4.0; Microsoft's Azure Linux vulnerability data, MIT. Modified: reformatted and linked to CVE records. Credits. On the distributions' own pages: Debian · Ubuntu · SUSE · openSUSE · Alpine.