CVE-2026-97043VulnerabilityPublished 11 Nov 2026

Building a malicious package that uses cgo could bypass "#cgo LDFLAGS" validation and cause unexpected code execution

Source GCVE Database

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Authoritative record:CVE-2026-97043· High

Not known to be exploited : upgrade to 1.27.4 or 1.26.11 soon.

Data as of 11 Nov 2026, 08:03 UTC

Severity

High

Rated High by Threat Radar's AI analysis · CVSS not yet scored by NVD

Thin evidence

One scorer or none

Patch: Available – fixed in 1.27.4, 1.26.11

Exploitation evidence

Disclosed: evidence found.
CVE published 11 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 10 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

ghsa-26gx-chjm-8pq7

What to do

Upgrade cmd/go and cmd/compile to 1.27.4 or 1.26.11.

Affected software

Product	Affected	Fixed in
Go toolchaincmd/go	Affected >=1.27.0-0 <1.27.4	Fixed in 1.27.4
Go toolchaincmd/go	Affected <1.26.11	Fixed in 1.26.11
Go toolchaincmd/compile	Affected >=1.27.0-0 <1.27.4	Fixed in 1.27.4
Go toolchaincmd/compile	Affected <1.26.11	Fixed in 1.26.11
Gocmd/go`pkg:golang/cmd/go`Other threats	Affected <1.26.11 >=1.27.0-0 <1.27.4	Fixed in 1.26.11 1.27.4
Gocmd/compile`pkg:golang/cmd/compile`Other threats	Affected <1.26.11 >=1.27.0-0 <1.27.4	Fixed in 1.26.11 1.27.4

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

The vendor has updated the go toolchain to properly handle backslash-escaped quotes and unquote pragma strings, and fixed the slice bounds check. Users should monitor official Go project advisories and update to fixed versions once available.

Description

A vulnerability in the Go toolchain allows a malicious package using cgo to bypass "#cgo LDFLAGS" validation, potentially leading to unexpected code execution during build time or causing the go command to panic. This occurs due to improper parsing of "//go:cgo_ldflag" directives, where backslash escapes were not handled correctly, allowing disallowed linker flags to be passed to the external linker. Additionally, a slice bounds check issue could cause a panic in the go command during LDFLAGS deduplication. The issue has been addressed by properly handling escaped quotes and fixing the slice bounds check.

Impact

A malicious package using cgo can bypass linker flag validation, potentially causing unexpected code execution during the build process or causing the go command to panic. This could lead to build-time compromise or denial of service in the build environment. There is no indication of active exploitation in the wild.

Summary

The vulnerability arises from a mismatch in how "cmd/cgo" generates "//go:cgo_ldflag" directives by quoting LDFLAGS arguments with strconv.Quote, while "cmd/compile" and "cmd/go" parse these directives by splitting on raw quote characters without handling backslash escapes or unquoting. This parsing discrepancy allows crafted quoting to smuggle disallowed linker flags or unvalidated linker search paths past the go command's flag checks, leading to unexpected code execution at build time. Furthermore, the go command's deduplication of LDFLAGS could panic due to an out-of-bounds slice index when certain flag list prefixes matched near the end of the slice. The fix involves proper handling of backslash-escaped quotes and unquoting pragma strings with strconv.Unquote, along with correcting the slice bounds check in processCgoOutputs.

References

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