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Vulnerability record · CVE-2026-42767 · published 9 June 2026

CVE-2026-42767: Openssl null pointer dereference vulnerability

OOpenssl · Openssl

Issue summary: An attacker-controlled CMP (Certificate Management Protocol) server could trigger a NULL pointer dereference in a CMP client application. Impact summary: A NULL pointer dereference causes a crash of the application and a Denial of Service. An attacker controlling a CMP server (or acting as a man-in-the-middle) could craft a CMP response containing a CRMF (Certificate Request Message Format) CertRepMessage with an EncryptedValue structure where the symmAlg field has an algorithm OID but no parameters field. When the OpenSSL CMP client processes this response, the NULL dereference occurs, causing a crash of the CMP client. Applications that process untrusted CMP/CRMF messages may be affected. 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.

5.9 CVSS 3.1 Medium EPSS 0.43% · top 65.6% CWE-476 · NULL pointer dereference
5.9CVSS 3.1 base score
0.43%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
6References
23 Jul 2026Last modified by NVD

Description

Issue summary: An attacker-controlled CMP (Certificate Management Protocol) server could trigger a NULL pointer dereference in a CMP client application. Impact summary: A NULL pointer dereference causes a crash of the application and a Denial of Service. An attacker controlling a CMP server (or acting as a man-in-the-middle) could craft a CMP response containing a CRMF (Certificate Request Message Format) CertRepMessage with an EncryptedValue structure where the symmAlg field has an algorithm OID but no parameters field. When the OpenSSL CMP client processes this response, the NULL dereference occurs, causing a crash of the CMP client. Applications that process untrusted CMP/CRMF messages may be affected. 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/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/openssl/openssl/commit/61a86a8cd73546c9fea916f3d304c1293e05c046 Patch
https://github.com/openssl/openssl/commit/665d5254083affde9982efca7c41dd01cacc8774 Patch
https://github.com/openssl/openssl/commit/810b722f772652ad48042bcc7ab07e3414b11d0f Patch
https://github.com/openssl/openssl/commit/b90ff3b1bd33b1c18e6a09936d097c2eddef8873 Patch
https://github.com/openssl/openssl/commit/e6f912907fc2ec82a0fd07aae55172c5e5e3d90d Patch
https://openssl-library.org/news/secadv/20260609.txt Vendor Advisory

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Source: NIST National Vulnerability Database (record CVE-2026-42767), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.