Is CVE-2026-39827 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-39827 being exploited in the wild.

How severe is CVE-2026-39827?

Medium severity, with a CVSS score of 6.5, published 22 May 2026.

Which products and versions are affected?

golang.org/x/crypto (Go) SEMVER:introduced=0,fixed=0.52.0; golang.org/x/crypto/ssh (Go) < 0.52.0.

Is there a fix for CVE-2026-39827?

Yes. golang.org/x/crypto (Go): upgrade to 0.52.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-39827 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-39827?

Check whether you run golang.org/x/crypto (Go) or golang.org/x/crypto/ssh (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-39827: Go x/crypto/ssh memory leak in channel rejection

Q: Is there a fix for CVE-2026-39827?

Yes. golang.org/x/crypto (Go): upgrade to 0.52.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

Q: How is CVE-2026-39827 attacked?

It is attacked over the network, in a software library.

Q: Am I affected by CVE-2026-39827?

Check whether you run golang.org/x/crypto (Go) or golang.org/x/crypto/ssh (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-39827 · Severity: medium · CVSS 6.5 · Published 2026-05-22

A vulnerability in the Go SSH library can allow a connected user to crash a server by repeatedly requesting new communication channels. When the server rejects these requests, it fails to properly clear them from memory, leading to a memory leak. This eventually exhausts system resources, causing the service to crash and become unavailable to all users.

Technologies: golang.org/x/crypto (Go), golang.org/x/crypto/ssh (Go). Vendors: Go.

Quick answers

Is CVE-2026-39827 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-39827 being exploited in the wild.
How severe is CVE-2026-39827?: Medium severity, with a CVSS score of 6.5, published 22 May 2026.
Which products and versions are affected?: golang.org/x/crypto (Go) SEMVER:introduced=0,fixed=0.52.0; golang.org/x/crypto/ssh (Go) < 0.52.0.
Is there a fix for CVE-2026-39827?: Yes. golang.org/x/crypto (Go): upgrade to 0.52.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-39827 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-39827?: Check whether you run golang.org/x/crypto (Go) or golang.org/x/crypto/ssh (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

golang.org/x/crypto (Go): upgrade to 0.52.0 or later
```
go get golang.org/x/crypto@v0.52.0
```

Technical details

A memory leak exists in golang.org/x/crypto/ssh due to improper handling of rejected channel requests. When a server rejects a channel open request using the 'channel.Reject' function, the internal state of the connection fails to remove the rejected channel object, preventing it from being garbage collected. An authenticated attacker can exploit this by repeatedly opening and forcing the rejection of channels, leading to unbounded memory growth and an eventual OOM (Out of Memory) crash. This affects any SSH server implementation using the vulnerable library versions. The issue is resolved in version 0.52.0 by ensuring rejected channels are properly removed from the connection's internal state.

Affected products

Go crypto/ssh < 0.52.0

Identifiers

CVE-2026-39827
GHSA-qpw4-5x99-6vjp
GO-2026-5016

Timeline

2019-10-24: other: Issue originally opened on GitHub
2026-05-22: advisory: NVD published date
2026-06-25: disclosed: GitHub Advisory published
2026-06-25: patched: Version 0.52.0 released

References

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