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CRITICAL

CVE-2026-39830

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

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.

Published Updated Sources: cvelistV5, Go

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.

Exploitation

Unreported

no source claims exploitation

EPSS

1%

chance of exploitation in 30 days

Affects

golang org x crypto

70 products listed

CVSS base

9.1

CRITICAL

CISA SSVC assessment

Three decision points CISA publishes for the CVEs it assesses · SSVC 2.0.3. A stakeholder decision, not a severity score.

CISA

Exploitation

None

none · proof-of-concept · active

Automatable

Yes

can an attacker script all four kill-chain steps

Technical impact

Partial

partial · total control of the vulnerable component

Affected scope

The catalog records vendors and products as separate lists, not pairs, so which product belongs to which vendor is not something this page can say.

Products (70)

golang org x crypto sshcryostat 4 on rhel 9red hat enterprise linux 10red hat enterprise linux 8red hat enterprise linux 8 8 telecommunications update servicered hat enterprise linux 8 8 update services for sap solutionsred hat enterprise linux 9red hat enterprise linux 9 6 extended update supportrhem 1 0 for rhel 9rhem 1 1 for rhel 10rhem 1 1 for rhel 9cert manager support for red hat openshift release 1 19cluster observability operator 1 5 0devworkspace operator 0 42logging subsystem for red hat openshift 6 6multicluster engine for kubernetes 2 1multicluster engine for kubernetes 2 11multicluster engine for kubernetes 2 8openshift api for data protection 1 3openshift api for data protection 1 4openshift api for data protection 1 5openshift api for data protection 1 6red hat advanced cluster management for kubernetes 2 16red hat advanced cluster security 4 9red hat advanced cluster security for kubernetes 4 10red hat advanced cluster security for kubernetes 4 11red hat edge manager 1 0red hat edge manager 1 1red hat openshift ai 3 3red hat openshift ai 3 4red hat openshift builds 1 7 3red hat openshift builds 1 8 1red hat openshift container platform 4 21red hat openshift data foundation 4 22red hat openshift gitops 1 19red hat openshift gitops 1 20red hat openstack platform 16 2red hat quay 3 10red hat quay 3 12red hat quay 3 15red hat quay 3 16red hat quay 3 9red hat trusted artifact signer 1 3red hat trusted artifact signer 1 4assisted installer for red hat openshift container platform 2confidential compute attestationexternaldns operatorexternal secrets operator for red hat openshiftmulticluster engine for kubernetesopenshift api for data protectionopenshift pipelinesopenshift serverlessred hat advanced cluster management for kubernetes 2red hat advanced cluster security 4red hat ceph storage 9red hat openshift ai rhoaired hat openshift container platform 4red hat openshift data foundation 4red hat openshift dev spacesred hat openshift for windows containersred hat openshift gitopsred hat openshift on awsred hat openshift virtualization 4red hat openstack platform 17 1red hat openstack platform 18 0red hat quay 3red hat trusted artifact signersecurity profiles operatorzero trust workload identity managerzero trust workload identity manager tech preview

Every base score collected

Sources score independently and disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactSource
9.1CVSS 3.1CRITICAL——cvelistV5

Weakness & attack patterns

  • CWE-772

Attack patterns reported against this CVE. The ATT&CK techniques below are inferred from its weakness class.

  • T1499.002Endpoint Denial of Service: Service Exhaustion Flood

References

25 on the record

Elsewhere on this site

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.