- Exploited
- No known exploitation
- Fix
- Fixed in 1.26.11, 1.27.4
- Who is exposed
- Not reported
Do first: Upgrade to a fixed version: 1.26.11, 1.27.4.
- Published
- Last modified
- Whether it needs action now or is a reference record, by fixed rules, with why. Last checked is when cve.now last re-read it.What do these mean? →
- Reference
- Last checked
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 10/100 · provisional
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
The Go command (cmd/go) can be tricked into unexpected code execution at build time or into writing files to arbitrary directories when it builds a malicious package that uses cgo with Clang or GCC. The flaw came from "-gen-*" and "-gnat*" flags in "#cgo" directives being allowed through, and those flags are now disallowed.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
Read the original description
When using Clang or GCC, building a malicious package that uses cgo could cause unexpected code execution at build time or write files to arbitrary directories via "-gen-*" or "-gnat*" flags in "#cgo" directives. The "-g*" wildcard in the compiler and linker flag allowlists previously matched Clang's two-argument "-gen-cdb-fragment-path <dir>" flag and GCC's two-argument "-gnatO <file>" flag, permitting compilation database fragments and sidecar output files to be written to arbitrary directories and desynchronizing flag argument parsing between the go command and the compiler driver so that subsequent arguments could be passed as unvalidated positional inputs to the linker. "-gen-*" and "-gnat*" flags are now disallowed in "#cgo" compiler and linker flags.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure?/25Unknown. No advisory context yet
- Reach10/20Affects Go packages
- Severity?/10Unknown. No CVSS score or vendor rating
- No patch0/5No signal
What would change the score
- Would score about 65 if added to CISA KEV
- Would score about 60 if CISA's SSVC rates exploitation active
- Would score about 32 if advisories confirm default setups are exposed
What to do
Upgrade to a fixed version: 1.26.11, 1.27.4.
Check your systems with an agent
Paste this into a coding or ops agent. It checks your systems read-only and reports a table per asset.
Check whether my systems are affected by CVE-2026-97035 (Unexpected code execution and arbitrary file write via Clang -gen- and GCC -gnat flags in cgo in cmd/go), using the cve.now data below. Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only. What cve.now has for CVE-2026-97035 (entry last updated 2026-11-11): Affected: - Go package cmd/go: fixed in 1.26.11; from 1.27.0-0, fixed in 1.27.4 - Go package toolchain: fixed in 1.26.11; from 1.27.0-0, fixed in 1.27.4 Fixed versions: 1.26.11, 1.27.4. Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory. CISA KEV: CVE-2026-97035 is not listed as of cve.now's last read. This KEV status is for CVE-2026-97035 only. If you also check another CVE, look up its own KEV status; never assume it from this one. How to check: - Packages (Go): find every lockfile in each project and run check_stack from the cve.now MCP server on each one. Compare the resolved versions, not the ranges a manifest declares, with the affected versions above. Include transitive dependencies. Verify against the linked advisories before concluding, and cite the date you read each one: - https://go.dev/cl/862148 - https://go.dev/issue/82575 - https://groups.google.com/g/golang-announce/c/iY8TY0wWgbM - https://pkg.go.dev/vuln/GO-2026-6856 Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing. Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action. Entry: https://cve.now/CVE-2026-97035 For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example get_vulnerability with id CVE-2026-97035.
Timeline
- CVE published
- First seen by cve.now
Affected versions
- cmd/goGo
fixed in 1.26.11; From 1.27.0-0 · fixed in 1.27.4
fixed in 1.26.11; From 1.27.0-0 · fixed in 1.27.4
Evidence 6
CVE record · 2
Establishes: The identifier and description.
- Record
- Record
Other links · 4
- Link
- Link
- Link
- Link
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-97035
Is CVE-2026-97035 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
Which versions are affected by CVE-2026-97035?
cmd/go (Go): before 1.26.11; from 1.27.0-0 before 1.27.4. toolchain (Go): before 1.26.11; from 1.27.0-0 before 1.27.4.Source: cve.now feed data
How do I fix CVE-2026-97035?
Upgrade to a fixed version: 1.26.11, 1.27.4.Source: cve.now feed data