SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityAnalyzed

CVE-2026-42764

Impact summary: NULL pointer dereference typically causes abnormal termination of the affected QUIC server process and a Denial of Service.

HIGH 7.5EPSS 1.17%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (1.17%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

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 default configuration not vulnerable to this issue. However if the SSL_LISTENER_FLAG_NO_VALIDATE is used with the SSL_new_listener() call, the address validation is disabled making the vulnerable code reachable. The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.

CVSS 3.1
7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS
1.17% probability · 66th percentile
CISA KEV
Not listed
Weakness
CWE-476
Affected
openssl/openssl
Source
openssl-security@openssl.org

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.