GO-2026-6179

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Source
https://pkg.go.dev/vuln/GO-2026-6179
Import Source
https://vuln.go.dev/ID/GO-2026-6179.json
JSON Data
https://api.osv.dev/v1/vulns/GO-2026-6179
Aliases
  • CVE-2026-56865
Downstream
Related
Published
2026-08-13T21:43:54Z
Modified
2026-08-14T09:41:58.033362708Z
Summary
Fix transparency log tile verification bypass in golang.org/x/mod/sumdb/tlog
Details

A malicious GOPROXY was previously capable of forging up to two sumdb tiles that allow for a requested module to bypass the GOSUMDB check and persist attacker-controlled module content to a local Go module cache.

This attack allows for a malicious GOPROXY to serve malicious module content that cannot be detected by evaluating the transparency log.

All tiles are now correctly verified against their parents.

In order to determine if you have been affected:

rm -r go.sum go.work.sum vendor/ && go mod tidy

Database specific 
{
    "url": "https://pkg.go.dev/vuln/GO-2026-6179",
    "review_status": "REVIEWED"
}
References
Credits
    • Filippo Valsorda (Geomys)

Affected packages

Go / toolchain

Package

Name
toolchain
View open source insights on deps.dev
Purl
pkg:golang/toolchain

Affected ranges

Type
SEMVER
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
1.25.13
Introduced
1.26.0-0
Fixed
1.26.6
Introduced
1.27.0-0
Fixed
1.27.0-rc.3

Ecosystem specific 

{
    "imports": [
        {
            "path": "cmd/go"
        }
    ]
}

Database specific

source 
"https://vuln.go.dev/ID/GO-2026-6179.json"

Go / golang.org/x/mod

Package

Name
golang.org/x/mod
View open source insights on deps.dev
Purl
pkg:golang/golang.org/x/mod

Affected ranges

Type
SEMVER
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
0.40.0

Ecosystem specific 

{
    "imports": [
        {
            "path": "golang.org/x/mod/sumdb/tlog",
            "symbols": [
                "tileHashReader.ReadHashes"
            ]
        }
    ]
}

Database specific

source 
"https://vuln.go.dev/ID/GO-2026-6179.json"