CVE-2026-22796
Issue summary: A type confusion vulnerability exists in the signature verification of signed PKCS#7 data where an ASN1_TYPE union member is accessed without first validating the type, causing an invalid or NULL pointer dereference when processing malformed PKCS#7 data.
Impact summary: An application performing signature verification of PKCS#7 data or calling directly the PKCS7_digest_from_attributes() function can be caused to dereference an invalid or NULL pointer when reading, resulting in a Denial of Service.
The function PKCS7_digest_from_attributes() accesses the message digest attribute value without validating its type. When the type is not V_ASN1_OCTET_STRING, this results in accessing invalid memory through the ASN1_TYPE union, causing a crash.
Exploiting this vulnerability requires an attacker to provide a malformed signed PKCS#7 to an application that verifies it. The impact of the exploit is just a Denial of Service, the PKCS7 API is legacy and applications should be using the CMS API instead. For these reasons the issue was assessed as Low severity.
The FIPS modules in 3.5, 3.4, 3.3 and 3.0 are not affected by this issue, as the PKCS#7 parsing implementation is outside the OpenSSL FIPS module boundary.
OpenSSL 3.6, 3.5, 3.4, 3.3, 3.0, 1.1.1 and 1.0.2 are vulnerable to this issue.
| Software | From | Fixed in |
|---|---|---|
| openssl / openssl | 1.0.2 | 1.0.2zn |
| openssl / openssl | 1.1.1 | 1.1.1ze |
| openssl / openssl | 3.0.0 | 3.0.19 |
| openssl / openssl | 3.3.0 | 3.3.6 |
| openssl / openssl | 3.4.0 | 3.4.4 |
| openssl / openssl | 3.5.0 | 3.5.5 |
| openssl / openssl | 3.6.0 | 3.6.1 |
- https://github.com/openssl/openssl/commit/2502e7b7d4c0cf4f972a881641fe09edc67aeec4
- https://github.com/openssl/openssl/commit/572844beca95068394c916626a6d3a490f831a49
- https://github.com/openssl/openssl/commit/7bbca05be55b129651d9df4bdb92becc45002c12
- https://github.com/openssl/openssl/commit/eeee3cbd4d682095ed431052f00403004596373e
- https://github.com/openssl/openssl/commit/ef2fb66ec571564d64d1c74a12e388a2a54d05d2
- https://openssl-library.org/news/secadv/20260127.txt
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Frequently Asked Questions
A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.
CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.
A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.
Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.
Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.
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