CVE-2026-39835: CWE-476: NULL Pointer Dereference in golang.org/x/crypto golang.org/x/crypto/ssh
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.
AI Analysis
Technical Summary
CVE-2026-39835 is a medium severity vulnerability (CVSS 5.3) in the golang.org/x/crypto/ssh package. The issue arises when SSH servers use CertChecker as a public key callback but do not set the IsUserAuthority or IsHostAuthority callbacks. In such cases, a client presenting a crafted SSH certificate can trigger a NULL pointer dereference, causing the server to panic and resulting in a denial of service. The vulnerability is addressed by modifying CertChecker to return an error rather than panicking when these callbacks are nil. Red Hat has issued advisories and security updates that include fixes for this vulnerability as part of Red Hat Edge Manager 1.1.3 for RHEL 9 and 10. No known exploits are reported in the wild.
Potential Impact
The vulnerability can cause a denial of service condition on SSH servers using the affected CertChecker configuration by triggering a panic via a crafted SSH certificate. There is no impact on confidentiality or integrity reported. The denial of service could disrupt availability of the SSH service.
Mitigation Recommendations
Red Hat has released security updates that fix this vulnerability as part of Red Hat Edge Manager 1.1.3 for RHEL 9 and 10. Users should apply these official patches to remediate the issue. Patch status is confirmed by the vendor advisory. No additional mitigation steps are indicated beyond applying the update.
CVE-2026-39835: CWE-476: NULL Pointer Dereference in golang.org/x/crypto golang.org/x/crypto/ssh
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.
CVSS v3.1
Score 5.3medium
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-39835 is a medium severity vulnerability (CVSS 5.3) in the golang.org/x/crypto/ssh package. The issue arises when SSH servers use CertChecker as a public key callback but do not set the IsUserAuthority or IsHostAuthority callbacks. In such cases, a client presenting a crafted SSH certificate can trigger a NULL pointer dereference, causing the server to panic and resulting in a denial of service. The vulnerability is addressed by modifying CertChecker to return an error rather than panicking when these callbacks are nil. Red Hat has issued advisories and security updates that include fixes for this vulnerability as part of Red Hat Edge Manager 1.1.3 for RHEL 9 and 10. No known exploits are reported in the wild.
Potential Impact
The vulnerability can cause a denial of service condition on SSH servers using the affected CertChecker configuration by triggering a panic via a crafted SSH certificate. There is no impact on confidentiality or integrity reported. The denial of service could disrupt availability of the SSH service.
Mitigation Recommendations
Red Hat has released security updates that fix this vulnerability as part of Red Hat Edge Manager 1.1.3 for RHEL 9 and 10. Users should apply these official patches to remediate the issue. Patch status is confirmed by the vendor advisory. No additional mitigation steps are indicated beyond applying the update.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- Go
- Date Reserved
- 2026-04-07T18:13:03.529Z
- Cvss Version
- null
- State
- PUBLISHED
- Remediation Level
- null
- Vendor Advisory Urls
- [{"url":"https://access.redhat.com/security/cve/CVE-2026-39835","vendor":"Red Hat"}]
Threat ID: 6a0fcdabe1370fbb487d5029
Added to database: 05/22/2026, 03:29:47 UTC
Last enriched: 07/25/2026, 21:45:17 UTC
Last updated: 07/31/2026, 21:26:40 UTC
Views: 81
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