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Critical 9.1Published May 21, 2026

CVE-2026-39830Invoking client can cause server deadlock on unexpected responses in golang.org/x/crypto/ssh

Updated under an hour ago ()

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It affects golang.org/x/crypto/ssh and 36 other products. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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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.

CVSS
9.1 CRITICAL (v3.1, CISA ADP)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Weakness (CWE)
CWE-833, CWE-772
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
Go
NVD analysis
Modified
Record last updated
Sep 18, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
golang.org/x/crypto golang.org/x/crypto/ssh
golang.org_x_crypto:ssh (from the name)
before 0.52.0
CNA record
from 4.2.0-19 not affected
CISA ADP
from 2:1.43.1-3.el10_2 not affected
CISA ADP
from 8080020260721142025.63b34585 not affected
CISA ADP
from 8080020260721142025.63b34585 not affected
CISA ADP
from 5:5.4.0-22.el9_6.5 not affected
CISA ADP
Red Hat RHEM 1.0 for RHEL 9
redhat:edge_manager
from 0:1.0.3-1.el9em not affected
CISA ADP
from 1786613805 not affected
CISA ADP
Red Hat Cluster Observability Operator 1.5.0
redhat:cluster_observability_operator
from 1787593637 not affected
CISA ADP
from 1782400868 not affected
CISA ADP

References

References

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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