CVE-2026-39835

Invoking server panic during CheckHostKey/Authenticate in golang.org/x/crypto/ssh

MEDIUM
5.3
CVSS Score
Published: May 22, 2026 at 02:31 AM UTC
Updated: September 18, 2026 at 01:18 PM UTC
21 products affected across 3 vendorsCryptoEnterprise LinuxOpenShift Container Platform

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Severity
MEDIUM5.3
Exploit prediction
EPSS 0.5%
SSVC
No known exploit

Description

SSH servers which use CertChecker as a public key callback without setting IsUserAuthority or IsHostAuthority could be caused to panic by a client presenting a certificate. CertChecker now returns an error instead of panicking when these callbacks are nil.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 0.52.0
Affected range stops below 0.52.0, so it looks safe — our inference, not a vendor statement
v < 0.52.0
Affected range stops below 0.52.0, so it looks safe — our inference, not a vendor statement
Vendor states this is fixed in 2 (unaffected)
Vendor states this is fixed in 10 (unaffected)
Vendor states this is fixed in 2:1.43.1-3.el10_2 (unaffected)
Vendor states this is fixed in 2:1.43.1-3.el9_8 (unaffected)
Vendor states this is fixed in 6:5.8.2-4.el9_8 (unaffected)
Vendor states this is fixed in 7:5.8.2-4.el10_2 (unaffected)
Vendor states this is fixed in 8100020260709093628.afee755d (unaffected)
All versions
All versions
Vendor states this is fixed in 1784158679 (unaffected)
Vendor states this is fixed in 1784564438 (unaffected)
Vendor states this is fixed in 1784738758 (unaffected)
Vendor states this is fixed in 1786637185 (unaffected)
Vendor states this is fixed in 1786912006 (unaffected)
All versions
Vendor states this is fixed in 1787001948 (unaffected)
Vendor states this is fixed in 1787002529 (unaffected)
Vendor states this is fixed in 1788181054 (unaffected)
Vendor states this is fixed in 1788181065 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

References (59)

Issue Tracking
Source: cverecord
https://go.dev/issue/79563
Issue Tracking
Source: cverecord
https://go.dev/cl/781660
Vendor Advisory
Source: cverecord
https://pkg.go.dev/vuln/GO-2026-5015
Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
https://access.redhat.com/errata/RHSA-2026:26546
Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
https://access.redhat.com/errata/RHSA-2026:26547
Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
https://access.redhat.com/security/cve/CVE-2026-39835
Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
https://bugzilla.redhat.com/show_bug.cgi?id=2480680

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.3MEDIUMCISA-ADP
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
LOW
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-295CWE-476

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