Invoking client can cause server deadlock on unexpected responses in golang.org/x/crypto/ssh
Summary
| CVE | CVE-2026-39830 |
|---|---|
| State | PUBLISHED |
| Assigner | Go |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-05-22 04:16:22 UTC |
| Updated | 2026-06-02 16:33:36 UTC |
| Description | A malicious SSH peer could send unsolicited global request responses to fill an internal buffer, blocking the connection's read loop. The blocked goroutine could not be released by calling Close(), resulting in a resource leak per connection. Unsolicited global responses are now discarded. |
Risk And Classification
Primary CVSS: v3.1 9.1 CRITICAL from ADP
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
EPSS: 0.000540000 probability, percentile 0.170520000 (date 2026-06-08)
Problem Types: CWE-119 | CWE-833: Deadlock
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | ADP | DECLARED | 9.1 | CRITICAL | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H |
| 3.1 | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | Secondary | 9.1 | CRITICAL | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H |
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
LowPrivileges Required
NoneUser Interaction
NoneScope
UnchangedConfidentiality
HighIntegrity
NoneAvailability
HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
NVD Known Affected Configurations (CPE 2.3)
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Golang.orgxcrypto | Golang.org/x/crypto/ssh | affected 0.52.0 semver | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| groups.google.com/g/golang-announce/c/a082jnz-LvI | [email protected] | groups.google.com | Mailing List |
| go.dev/cl/781664 | [email protected] | go.dev | Issue Tracking |
| pkg.go.dev/vuln/GO-2026-5017 | [email protected] | pkg.go.dev | Vendor Advisory |
| go.dev/cl/781640 | [email protected] | go.dev | Issue Tracking |
| go.dev/issue/79564 | [email protected] | go.dev | Issue Tracking |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: NCC Group Cryptography Services, sponsored by Teleport (en)
There are currently no legacy QID mappings associated with this CVE.