Module substitution via skipped checksum verification
Published Oct 8, 2026 · Updated Oct 8, 2026
Checksum bypass in Go Command allows attackers to substitute the bundled FIPS module through a malicious project and module proxy. The cmd/go/internal/modfetch DownloadDir function accepts golang.org/fips140 cache entries without requiring a ziphash, allowing attacker-supplied module contents to replace the trusted bundle. Exploitation requires operation inside a malicious project and connection to its malicious module proxy; the established consequence is arbitrary module substitution.
Summary
What happened
Checksum bypass in Go Command allows attackers to substitute the bundled FIPS module through a malicious project and module proxy. The cmd/go/internal/modfetch DownloadDir function accepts golang.org/fips140 cache entries without requiring a ziphash, allowing attacker-supplied module contents to replace the trusted bundle. Exploitation requires operation inside a malicious project and connection to its malicious module proxy; the established consequence is arbitrary module substitution.
The record
- CVE
- CVE-2026-94444
- Published
- Oct 8, 2026
- Updated
- Oct 8, 2026
- Vendor
- Go Project
- Product
- Go Command
- Classifications
- T1195.001
- Attack vector
- network
- Privileges
- Unavailable
Timeline
How it unfolded
- Oct 8, 2026CVE publishedPublication date reported by the CVE source.
- Oct 8, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <1.26.9
- Affected versionversion=1.27.0-0 <1.27.2
What conditions does exploitation require?
What is affected?
Published CVSS scores
No CVSS assessment is available in this record.
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Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Activity data is delayed. The latest report is Sep 28, 2026.
Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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