---
id: CVE-2026-22796
title: ASN1_TYPE Type Confusion in the PKCS7_digest_from_attributes() function
summary: |-
  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 p…
severity: medium
cvss: 5.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L'
cvssSource: adp
cwe:
  - CWE-754
vendor: OpenSSL
product: OpenSSL
affected:
  - OpenSSL >= 3.6.0 < 3.6.1
  - OpenSSL >= 3.5.0 < 3.5.5
  - OpenSSL >= 3.4.0 < 3.4.4
  - OpenSSL >= 3.3.0 < 3.3.6
  - OpenSSL >= 3.0.0 < 3.0.19
  - OpenSSL >= 1.1.1 < 1.1.1ze
  - OpenSSL >= 1.0.2 < 1.0.2zn
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-01-27T16:27:50.351586Z'
published: '2026-01-27'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T01:12:21.460Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-22796'
references:
  - url: 'https://openssl-library.org/news/secadv/20260127.txt'
    label: OpenSSL Advisory
  - url: >-
      https://github.com/openssl/openssl/commit/ef2fb66ec571564d64d1c74a12e388a2a54d05d2
    label: 3.6.1 git commit
  - url: >-
      https://github.com/openssl/openssl/commit/2502e7b7d4c0cf4f972a881641fe09edc67aeec4
    label: 3.5.5 git commit
  - url: >-
      https://github.com/openssl/openssl/commit/7bbca05be55b129651d9df4bdb92becc45002c12
    label: 3.4.4 git commit
  - url: >-
      https://github.com/openssl/openssl/commit/eeee3cbd4d682095ed431052f00403004596373e
    label: 3.3.6 git commit
  - url: >-
      https://github.com/openssl/openssl/commit/572844beca95068394c916626a6d3a490f831a49
    label: 3.0.19 git commit
tags:
  - cve.org
epss: 0.00576
epssPercentile: 0.46161
ingestedAt: '2026-10-15T05:52:46.047Z'
---

## Overview

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.

## Affected

- `OpenSSL >= 3.6.0 < 3.6.1`
- `OpenSSL >= 3.5.0 < 3.5.5`
- `OpenSSL >= 3.4.0 < 3.4.4`
- `OpenSSL >= 3.3.0 < 3.3.6`
- `OpenSSL >= 3.0.0 < 3.0.19`
- `OpenSSL >= 1.1.1 < 1.1.1ze`
- `OpenSSL >= 1.0.2 < 1.0.2zn`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.