Vulnerability · Published May 22, 2026 · Assigned by Go
CVE-2026-39827Invoking memory leak when rejecting channels can lead to DoS in golang.org/x/crypto/ssh
Medium 6.5
In plain English
A medium-severity security flaw in golang.org/x/crypto/ssh from golang.org/x/crypto. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 21% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)6.5Medium
Exploit odds (30 days)0.3%top 79.5% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
An authenticated SSH client that repeatedly opened channels which were rejected by the server caused unbounded memory growth, eventually crashing the server process and affecting all connected users. Rejected channels are now properly removed from the connection's internal state and released for garbage collection.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | golang-go.crypto | no fix listed | DEBIAN-CVE-2026-39827 |
| Debian:13 | golang-go.crypto | no fix listed | DEBIAN-CVE-2026-39827 |
| Debian:14 | golang-go.crypto | 1:0.52.0-1 | DEBIAN-CVE-2026-39827 |
| Go | golang.org/x/crypto | 0.52.0 | GO-2026-5016 |
| Go | golang.org/x/crypto | 0.52.0 | GHSA-qpw4-5x99-6vjp |
| Ubuntu:25.10 | golang-go.crypto | no fix listed | UBUNTU-CVE-2026-39827 |
| Ubuntu:26.10 | golang-go.crypto | no fix listed | UBUNTU-CVE-2026-39827 |
| Ubuntu:22.04:LTS | google-guest-agent | no fix listed | UBUNTU-CVE-2026-39827 |
| Ubuntu:24.04:LTS | google-guest-agent | no fix listed | UBUNTU-CVE-2026-39827 |
| Ubuntu:25.10 | google-guest-agent | no fix listed | UBUNTU-CVE-2026-39827 |
| Ubuntu:26.04:LTS | google-guest-agent | no fix listed | UBUNTU-CVE-2026-39827 |
| Ubuntu:26.10 | google-guest-agent | no fix listed | UBUNTU-CVE-2026-39827 |
| Ubuntu:22.04:LTS | snapd | no fix listed | UBUNTU-CVE-2026-39827 |
| Ubuntu:24.04:LTS | snapd | no fix listed | UBUNTU-CVE-2026-39827 |
| Ubuntu:25.10 | snapd | no fix listed | UBUNTU-CVE-2026-39827 |
| Ubuntu:26.04:LTS | snapd | no fix listed | UBUNTU-CVE-2026-39827 |
| Ubuntu:26.10 | snapd | no fix listed | UBUNTU-CVE-2026-39827 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| golang.org/x/crypto | golang.org/x/crypto/ssh | 0 – before 0.52.0 |