CVE-2026-42764

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 SSLLISTENERFLAGNOVALIDATE is used with the SSLnewlistener() 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.

Database specific

{
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42764.json",
    "cwe_ids": [
        "CWE-476"
    ],
    "cna_assigner": "openssl"
}

References

Affected packages

Git / github.com/openssl/openssl

Affected ranges

Type

GIT

Repo

https://github.com/openssl/openssl

Events

Introduced

11b7b6ea3b65a584e1d31408ed1bdb139465cffd

Fixed

1e963a8680ec78ad2072792c7a1a71f3c530bd2e

Introduced

7b371d80d959ec9ab4139d09d78e83c090de9779

Fixed

aae016bfd52fcad2bc9657c2c782cfdf73b1ed5f

Introduced

636dfadc70ce26f2473870570bfd9ec352806b1d

Fixed

8cf17aaeb4599f8af87fefd810b5b5fee90fe69e

Database specific

{
    "extracted_events": [
        {
            "introduced": "4.0.0"
        },
        {
            "fixed": "4.0.1"
        },
        {
            "introduced": "3.6.0"
        },
        {
            "fixed": "3.6.3"
        },
        {
            "introduced": "3.5.0"
        },
        {
            "fixed": "3.5.7"
        }
    ],
    "source": "AFFECTED_FIELD"
}

Affected versions

3.*

3.5-POST-CLANG-FORMAT-WEBKIT

3.5-PRE-CLANG-FORMAT-WEBKIT

3.6-POST-CLANG-FORMAT-WEBKIT

3.6-PRE-CLANG-FORMAT-WEBKIT

openssl-3.*

openssl-3.5.0

openssl-3.5.1

openssl-3.5.2

openssl-3.5.3

openssl-3.5.4

openssl-3.5.5

openssl-3.5.6

openssl-3.6.0

openssl-3.6.1

openssl-3.6.2

openssl-4.*

openssl-4.0.0

Database specific

source

"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-42764.json"