OpenSSL up to 4.0.0 null pointer dereference

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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5.5$0-$5k0.00

Summaryinfo

A vulnerability was found in OpenSSL up to 3.0.20/3.4.5/3.5.6/3.6.2/4.0.0. It has been declared as problematic. Affected by this vulnerability is an unknown functionality. Such manipulation leads to null pointer dereference. This vulnerability is listed as CVE-2026-42766. The attack may be performed from remote. There is no available exploit. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in OpenSSL up to 3.0.20/3.4.5/3.5.6/3.6.2/4.0.0. Affected by this issue is some unknown processing. The manipulation with an unknown input leads to a null pointer dereference vulnerability. Using CWE to declare the problem leads to CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. Impacted is availability. CVE summarizes:

Issue summary: A specially crafted password-encrypted CMS message can trigger a NULL pointer dereference during CMS decryption. Impact summary: This NULL pointer dereference leads to an application crash and a Denial of Service. The CMS PasswordRecipientInfo.keyDerivationAlgorithm field is defined as OPTIONAL in the ASN.1 specification and may therefore be absent in specially crafted inputs. During the password-based CMS decryption the OpenSSL CMS implementation dereferences this field without first checking whether it was present. An attacker who supplies such a CMS message to an application performing password-based CMS decryption can trigger an application crash, leading to a Denial of Service. Applications that process password-encrypted CMS 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.

The advisory is available at openssl-library.org. This vulnerability is handled as CVE-2026-42766 since 04/29/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. The technical details are unknown and an exploit is not available. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 06/30/2026).

The vulnerability scanner Nessus provides a plugin with the ID 320350 (Linux Distros Unpatched Vulnerability : CVE-2026-42766), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 1.0.2zq, 1.1.1zh, 3.0.21, 3.4.6, 3.5.7, 3.6.3 or 4.0.1 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (320350) and CERT Bund (WID-SEC-2026-1852). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Affected

  • Debian Linux
  • Amazon Linux 2
  • FreeBSD Project FreeBSD OS
  • Red Hat Enterprise Linux
  • Fedora Linux
  • Ubuntu Linux
  • SUSE Linux
  • Oracle Linux
  • NetApp FAS
  • NetApp AFF
  • SUSE openSUSE
  • RESF Rocky Linux
  • Open Source OpenSSL

Productinfo

Type

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.6
VulDB Meta Temp Score: 5.5

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

ADP CISA Base Score: 5.9
ADP CISA Vector: 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Null pointer dereference
CWE: CWE-476 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 320350
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2026-42766

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: OpenSSL 1.0.2zq/1.1.1zh/3.0.21/3.4.6/3.5.7/3.6.3/4.0.1

Timelineinfo

04/29/2026 CVE reserved
06/09/2026 +41 days Advisory disclosed
06/09/2026 +0 days VulDB entry created
06/30/2026 +21 days VulDB entry last update

Sourcesinfo

Product: openssl.org

Advisory: openssl-library.org
Status: Confirmed

CVE: CVE-2026-42766 (🔒)
GCVE (CVE): GCVE-0-2026-42766
GCVE (VulDB): GCVE-100-369578
CERT Bund: WID-SEC-2026-1852 - OpenSSL: Mehrere Schwachstellen

Entryinfo

Created: 06/09/2026 19:11
Updated: 06/30/2026 11:07
Changes: 06/09/2026 19:11 (54), 06/10/2026 14:14 (2), 06/13/2026 22:50 (11), 06/30/2026 11:07 (7)
Complete: 🔍
Cache ID: 216::103

If you want to get best quality of vulnerability data, you may have to visit VulDB.

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