golang-1.19, golang-1.24 and 1 more products — security advisory
A malicious module proxy can exploit a flaw in the go command's validation of module checksums to bypass checksum database validation. This vulnerability affects any user using an untrusted module proxy (GOMODPROXY) or checksum database (GOSUMDB). A malicious module proxy can serve altered versions of the Go toolchain. When selecting a different version of the Go toolchain than the currently installed toolchain (due to the GOTOOLCHAIN environment variable, or a go.work or go.mod with a toolchain line), the go command will download and execute a toolchain provided by the module proxy. A malicious module proxy can bypass checksum database validation for this downloaded toolchain. Since this vulnerability affects the security of toolchain downloads, setting GOTOOLCHAIN to a fixed version is not sufficient. You must upgrade your base Go toolchain. The go tool always validates the hash of a toolchain before executing it, so fixed versions will refuse to execute any cached, altered versions of the toolchain. The go tool trusts go.sum files to contain accurate hashes of the current module's dependencies. A malicious proxy exploiting this vulnerability to serve an altered module will have caused an incorrect hash to be recorded in the go.sum. Users who have configured a non-trusted GOPROXY can determine if they have been affected by running "rm go.sum ; go mod tidy ; go mod verify", which will revalidate all dependencies of the current module. The specific flaw in more detail: The go
- Products
- golang-1.19, golang-1.24, golang-1.26
- Affected versions
- 1.19.10-1, 1.19.10-2, 1.19.11-1, 1.19.12-1, 1.19.12-2, 1.19.12-2~bpo11+1, 1.19.12-2~bpo12+1, 1.19.13-1, 1.19.13-1~bpo11+1, 1.19.13-1~bpo12+1, 1.19.8-2, 1.19.9-1, 1.24.12-1, 1.24.13-1, 1.24.13-2, 1.24.4-1, 1.24.4-2, 1.24.4-3, 1.24.4-4, 1.24.7-1, 1.24.8-1, 1.24.9-1, 1.26.0-1, 1.26.1-1, 1.26.2-1, 1.26.2-2, 1.26.2-3, 1.26.3-1~bpo13+1, 1.26~rc2-1, 1.26~rc3-1, 1.26~rc3-2
- Fixed versions
- 1.26.3-1
- CVEs
- CVE-2026-42501
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 30 Oct 2026, 06:34 UTC · Revision 1
Source evidence
A malicious module proxy can exploit a flaw in the go command's validation of module checksums to bypass checksum database validation. This vulnerability affects any user using an untrusted module proxy (GOMODPROXY) or checksum database (GOSUMDB). A malicious module proxy can serve altered versions of the Go toolchain. When selecting a different version of the Go toolchain than the currently installed toolchain (due to the GOTOOLCHAIN environment variable, or a go.work or go.mod with a toolchain line), the go command will download and execute a toolchain provided by the module proxy. A malicious module proxy can bypass checksum database validation for this downloaded toolchain. Since this vulnerability affects the security of toolchain downloads, setting GOTOOLCHAIN to a fixed version is not sufficient. You must upgrade your base Go toolchain. The go tool always validates the hash of a toolchain before executing it, so fixed versions will refuse to execute any cached, altered versions of the toolchain. The go tool trusts go.sum files to contain accurate hashes of the current module's dependencies. A malicious proxy exploiting this vulnerability to serve an altered module will have caused an incorrect hash to be recorded in the go.sum. Users who have configured a non-trusted GOPROXY can determine if they have been affected by running "rm go.sum ; go mod tidy ; go mod verify", which will revalidate all dependencies of the current module. The specific flaw in more detail: The go
osv:DEBIAN-CVE-2026-42501
golang-1.19
Fixed versions: Not specified
golang-1.24
Fixed versions: Not specified
golang-1.26
Fixed versions: 1.26.3-1
Complete source record
{
"id": "902a671f4b097a63143c327aadbacaa3dcf20ffa59a4bbf01d6a7529f7cf4dd9",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-42501",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2026-42501",
"summary": "A malicious module proxy can exploit a flaw in the go command's validation of module checksums to bypass checksum database validation. This vulnerability affects any user using an untrusted module proxy (GOMODPROXY) or checksum database (GOSUMDB). A malicious module proxy can serve altered versions of the Go toolchain. When selecting a different version of the Go toolchain than the currently installed toolchain (due to the GOTOOLCHAIN environment variable, or a go.work or go.mod with a toolchain line), the go command will download and execute a toolchain provided by the module proxy. A malicious module proxy can bypass checksum database validation for this downloaded toolchain. Since this vulnerability affects the security of toolchain downloads, setting GOTOOLCHAIN to a fixed version is not sufficient. You must upgrade your base Go toolchain. The go tool always validates the hash of a toolchain before executing it, so fixed versions will refuse to execute any cached, altered versions of the toolchain. The go tool trusts go.sum files to contain accurate hashes of the current module's dependencies. A malicious proxy exploiting this vulnerability to serve an altered module will have caused an incorrect hash to be recorded in the go.sum. Users who have configured a non-trusted GOPROXY can determine if they have been affected by running \"rm go.sum ; go mod tidy ; go mod verify\", which will revalidate all dependencies of the current module. The specific flaw in more detail: The go",
"evidence": "osv:DEBIAN-CVE-2026-42501",
"products": [
{
"name": {
"value": "golang-1.19",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "1.19.10-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.19.10-2",
"evidence": "/affected/0/versions"
},
{
"value": "1.19.11-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.19.12-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.19.12-2",
"evidence": "/affected/0/versions"
},
{
"value": "1.19.12-2~bpo11+1",
"evidence": "/affected/0/versions"
},
{
"value": "1.19.12-2~bpo12+1",
"evidence": "/affected/0/versions"
},
{
"value": "1.19.13-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.19.13-1~bpo11+1",
"evidence": "/affected/0/versions"
},
{
"value": "1.19.13-1~bpo12+1",
"evidence": "/affected/0/versions"
},
{
"value": "1.19.8-2",
"evidence": "/affected/0/versions"
},
{
"value": "1.19.9-1",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
"value": "golang-1.24",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "1.24.12-1",
"evidence": "/affected/1/versions"
},
{
"value": "1.24.13-1",
"evidence": "/affected/1/versions"
},
{
"value": "1.24.13-2",
"evidence": "/affected/1/versions"
},
{
"value": "1.24.4-1",
"evidence": "/affected/1/versions"
},
{
"value": "1.24.4-2",
"evidence": "/affected/1/versions"
},
{
"value": "1.24.4-3",
"evidence": "/affected/1/versions"
},
{
"value": "1.24.4-4",
"evidence": "/affected/1/versions"
},
{
"value": "1.24.7-1",
"evidence": "/affected/1/versions"
},
{
"value": "1.24.8-1",
"evidence": "/affected/1/versions"
},
{
"value": "1.24.9-1",
"evidence": "/affected/1/versions"
}
]
},
{
"name": {
"value": "golang-1.26",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "1.26.3-1",
"evidence": "/affected/2/ranges"
}
],
"affected_versions": [
{
"value": "1.26.0-1",
"evidence": "/affected/2/versions"
},
{
"value": "1.26.1-1",
"evidence": "/affected/2/versions"
},
{
"value": "1.26.2-1",
"evidence": "/affected/2/versions"
},
{
"value": "1.26.2-2",
"evidence": "/affected/2/versions"
},
{
"value": "1.26.2-3",
"evidence": "/affected/2/versions"
},
{
"value": "1.26.3-1~bpo13+1",
"evidence": "/affected/2/versions"
},
{
"value": "1.26~rc2-1",
"evidence": "/affected/2/versions"
},
{
"value": "1.26~rc3-1",
"evidence": "/affected/2/versions"
},
{
"value": "1.26~rc3-2",
"evidence": "/affected/2/versions"
}
]
}
],
"severity": "high",
"structured": {
"id": "DEBIAN-CVE-2026-42501",
"aliases": [
"DEBIAN-CVE-2026-42501"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "golang-1.19",
"purl": "pkg:deb/debian/golang-1.19?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"versions": [
"1.19.10-1",
"1.19.10-2",
"1.19.11-1",
"1.19.12-1",
"1.19.12-2",
"1.19.12-2~bpo11+1",
"1.19.12-2~bpo12+1",
"1.19.13-1",
"1.19.13-1~bpo11+1",
"1.19.13-1~bpo12+1",
"1.19.8-2",
"1.19.9-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-42501.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "golang-1.24",
"purl": "pkg:deb/debian/golang-1.24?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"versions": [
"1.24.12-1",
"1.24.13-1",
"1.24.13-2",
"1.24.4-1",
"1.24.4-2",
"1.24.4-3",
"1.24.4-4",
"1.24.7-1",
"1.24.8-1",
"1.24.9-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-42501.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1.26.3-1"
}
]
}
],
"package": {
"name": "golang-1.26",
"purl": "pkg:deb/debian/golang-1.26?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"versions": [
"1.26.0-1",
"1.26.1-1",
"1.26.2-1",
"1.26.2-2",
"1.26.2-3",
"1.26.3-1~bpo13+1",
"1.26~rc2-1",
"1.26~rc3-1",
"1.26~rc3-2"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-42501.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
],
"modified": "2026-10-12T11:00:44.105954891Z",
"provider": "osv",
"upstream": [
"CVE-2026-42501"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2026-42501"
]
},
"related_cves": [
{
"value": "CVE-2026-42501",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 299778,
"published_at": "2026-05-07T20:16:44.643+00:00"
}