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CVE-2026-97043GO-2026-6848

Unexpected code execution via escaped quotes in //go:cgo_ldflag in cmd/go and cmd/compile

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
Reference
Last checked
10/100 · provisional
None on Exploit-DB, Metasploit or GitHub

Summary

The Go toolchain's cmd/go and cmd/compile tools mishandle escaped quotes in cgo linker directives, which can let a malicious package that uses cgo smuggle disallowed linker flags past validation and run unexpected code at build time, or make the go command panic. The flaw is also triggered by a malformed LDFLAGS list during deduplication in cmd/go.

Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.

Read the original description

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:cgo_ldflag" directives. When "cmd/cgo" generates "_cgo_gotypes.go", it quotes each "#cgo LDFLAGS" argument with strconv.Quote in a "//go:cgo_ldflag" 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.

cve.now Index

10Pcve.now Index 10 of 100 · methodology v3 · provisional
  • 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

How the score works · Rankings

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-2026-97043 (Unexpected code execution via escaped quotes in //go:cgo_ldflag in cmd/go and cmd/compile), 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-2026-97043 (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 cmd/compile: 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-2026-97043 is not listed as of cve.now's last read.
This KEV status is for CVE-2026-97043 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/862156
- https://go.dev/issue/82567
- https://groups.google.com/g/golang-announce/c/iY8TY0wWgbM
- https://pkg.go.dev/vuln/GO-2026-6848
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-2026-97043
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-2026-97043.

Timeline

  1. CVE published
  2. First seen by cve.now

Affected versions

  • 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

  • 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.

  1. Record
  2. Record

Other links · 4

  1. Link
  2. Link
  3. Link
  4. Link

Corrections

None so far.

Something wrong on this page? Report an error. Every fix is listed here.

Questions about CVE-2026-97043

Is CVE-2026-97043 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-2026-97043?

cmd/go (Go): before 1.26.11; from 1.27.0-0 before 1.27.4. cmd/compile (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-2026-97043?

Upgrade to a fixed version: 1.26.11, 1.27.4.Source: cve.now feed data

Sources

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