CVE-2026-22796: ASN1_TYPE Type Confusion in the PKCS7_digest_from_attributes() function
- Is it exploited?
Not on CISA's list. CISA has not added it to the Known Exploited Vulnerabilities catalog as of . If CISA adds it, this page shows it as known exploited.
- How likely is exploitation in the next 30 days?
- 0.6%
EPSS score, percentile 48.1 of all scored records. A probability estimated by FIRST, not a report of exploitation.
- How severe?
- 5.3 Medium
CVSS v3.1 base score, from CISA's enrichment of the record
- What should I do?
CISA has set no required action, because the vulnerability is not in KEV.
- Which versions are affected?
Affected
- from 3.6.0 to before 3.6.1
- from 3.5.0 to before 3.5.5
- from 3.4.0 to before 3.4.4
- from 3.3.0 to before 3.3.6
- from 3.0.0 to before 3.0.19
- from 1.1.1 to before 1.1.1ze
and 1 more in the table below
Source: CISA KEV 2026.10.29, as of ; FIRST EPSS, as of ; CVE List, as of . About the data.
What to do
Advisories and patches
- 3.6.1 git commit
- 3.5.5 git commit
- 3.4.4 git commit
- 3.3.6 git commit
- 3.0.19 git commit
- OpenSSL Advisory
This summary is based on the CVE record as of . Check the vendor's advisory before you act: affected versions and fixes can change.
Affected products and versions
As listed in the CVE record.
| Status | Versions |
|---|---|
| Affected | from 3.6.0 to before 3.6.1 |
| Affected | from 3.5.0 to before 3.5.5 |
| Affected | from 3.4.0 to before 3.4.4 |
| Affected | from 3.3.0 to before 3.3.6 |
| Affected | from 3.0.0 to before 3.0.19 |
| Affected | from 1.1.1 to before 1.1.1ze |
| Affected | from 1.0.2 to before 1.0.2zn |
Versions not listed are: unaffected.
Source: CVE List, as of . About the data.
About this vulnerability
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_attrib…
Summary: CVE record, as of .
- CISA has not added CVE-2026-22796 to its Known Exploited Vulnerabilities (KEV) catalog, as of 29 Oct 2026.
- The CVE record was published on 27 Jan 2026.
- The CVE record carries a CVSS v3.1 base score of 5.3 (Medium), taken from CISA's enrichment of the record.
- FIRST's EPSS model puts the probability of exploitation in the next 30 days at 0.6% (percentile 48.1), as of 29 Oct 2026. EPSS is a statistical estimate, not a report of exploitation.
- CISA's SSVC assessment in the CVE record: exploitation none, automatable yes, technical impact partial.
- The credits in the CVE record name AISLE as finder.
Source: CISA KEV 2026.10.29, as of ; CVE List, as of ; FIRST EPSS, as of . About the data.
Description
ASN1_TYPE Type Confusion in the PKCS7_digest_from_attributes() function
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.
Source: CVE List, as of . About the data.
Weakness
CWE-754
- CWE-754: Improper Check for Unusual or Exceptional Conditions
CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record.
Timeline
| Date | Event |
|---|---|
| CVE record published | |
| CVE record last updated |
Known exploited OpenSSL vulnerabilities
- CVE-2014-0160: OpenSSL Information Disclosure Vulnerability