Review reviewHigh

CVE-2026-42764

OpenSSL OpenSSL, openssl

Issue summary: Receiving a QUIC initial packet with an invalid token may trigger a NULL pointer dereference in the OpenSSL QUIC server with address validation disabled. Impact summary: NULL pointer dereference typically causes abnormal termination of the affected QUIC server process and a Denial of Service. If the address validation is disabled in the OpenSSL QUIC server implementation, an attacker can crash the server by sending an initial packet with an invalid or expired token. By default, the client address validation is enabled in the OpenSSL QUIC server implementation, which makes the...

CVSS: 7.5
EPSS: 1.17%
CISA KEV: Not listed
Published: 2026.06.10

PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV

Exploit probability1.17%

Technical severityCVSS 7.5

Vulnerability overview

Affected product and versions

Product: OpenSSL OpenSSL, openssl
Affected versions: >= 4.0.0 < 4.0.1, >= 3.6.0 < 3.6.3, >= 3.5.0 < 3.5.7, 4.0.0
Fixed versions: 3.5.7, 3.6.3

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide

1
Identify
Confirm that OpenSSL OpenSSL, openssl and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE: CWE-476