Critical
Invoking infinite loop on large channel writes in golang.org/x/crypto/ssh
Type: advisorySources: OSV
When writing data larger than 4GB in a single Write call on an SSH channel, an integer overflow in the internal payload size calculation caused the write loop to spin indefinitely, sending empty packets without making progress. The size comparison now uses int64 to prevent truncation.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2026-39834
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 7 Nov 2026, 18:13 UTC · Revision 1
Source evidence
Invoking infinite loop on large channel writes in golang.org/x/crypto/ssh
core-osv · Original sourcePublished 22 May 2026, 02:31 UTC
When writing data larger than 4GB in a single Write call on an SSH channel, an integer overflow in the internal payload size calculation caused the write loop to spin indefinitely, sending empty packets without making progress. The size comparison now uses int64 to prevent truncation.
osv:CVE-2026-39834
Complete source record
{
"id": "1bb88bd5c16436ad1c4819522b43497b0a7f5a5ac1326fcfedd198e04da75399",
"url": "https://osv.dev/vulnerability/CVE-2026-39834",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "Invoking infinite loop on large channel writes in golang.org/x/crypto/ssh",
"summary": "When writing data larger than 4GB in a single Write call on an SSH channel, an integer overflow in the internal payload size calculation caused the write loop to spin indefinitely, sending empty packets without making progress. The size comparison now uses int64 to prevent truncation.",
"evidence": "osv:CVE-2026-39834",
"products": [],
"severity": "critical",
"structured": {
"id": "CVE-2026-39834",
"aliases": [
"CVE-2026-39834",
"GHSA-rm3j-f69w-wqmq",
"GO-2026-5020"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/golang/crypto",
"type": "GIT",
"events": [
{
"introduced": "0"
},
{
"fixed": "a1c0d9929856c8aba2b31f079340f00578eda803"
}
],
"database_specific": {
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{
"cpe": "cpe:2.3:a:golang:crypto:*:*:*:*:*:go:*:*",
"range": [
{
"introduced": "0"
},
{
"fixed": "0.52.0"
}
],
"source": "CPE_RANGE"
}
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}
}
],
"versions": [
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"v0.5.0",
"v0.4.0",
"v0.3.0",
"v0.2.0",
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],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-39834.json"
}
}
],
"modified": "2026-10-28T02:30:51.403832468Z",
"provider": "osv",
"references": [
"https://go.dev/cl/781663",
"https://go.dev/issue/79567",
"https://groups.google.com/g/golang-announce/c/a082jnz-LvI",
"https://pkg.go.dev",
"https://pkg.go.dev/vuln/GO-2026-5020",
"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/39xxx/CVE-2026-39834.json",
"https://nvd.nist.gov/vuln/detail/CVE-2026-39834"
],
"provider_metadata": {
"cna_assigner": "Go",
"unresolved_ranges": [
{
"extracted_events": [
{
"range": [
{
"fixed": "0.52.0"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StandardRange"
}
]
}
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/39xxx/CVE-2026-39834.json"
}
},
"related_cves": [
{
"value": "CVE-2026-39834",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 520063,
"published_at": "2026-05-22T02:31:27.54+00:00"
}