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Mallory
Medium

Missing ASN1_TYPE validation in OpenSSL PKCS#12 parsing

IdentifiersCVE-2026-22795CWE-843

CVE-2026-22795 is a type confusion vulnerability in OpenSSL's PKCS#12 parsing code. When processing a malformed PKCS#12 file, the code accesses an ASN1_TYPE union member without first validating that the ASN.1 object is of the expected type. This missing ASN1_TYPE validation can cause an invalid or NULL pointer dereference on memory read. The issue is described as an invalid pointer read constrained to a 1-byte address space (0x00-0xFF), corresponding to the zero page on most modern operating systems, which makes the outcome a reliable crash rather than controlled code execution. Affected versions are OpenSSL 3.6, 3.5, 3.4, 3.3, 3.0, and 1.1.1; OpenSSL 1.0.2 is not affected. The OpenSSL FIPS modules in 3.5, 3.4, 3.3, and 3.0 are not affected because the PKCS#12 implementation is outside the FIPS module boundary.

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ANALYST BRIEF

Impact, mitigation & remediation

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Impact

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Successful exploitation causes a denial of service by crashing the application that parses the malicious PKCS#12 file. Based on the provided advisory, the invalid pointer read is limited to addresses 0x00-0xFF, which on modern systems typically maps to unmapped zero-page memory, so the practical impact is an invalid or NULL pointer dereference and process termination rather than code execution. Severity was assessed as Low.

Mitigation

If you can’t patch tonight, do this now.

Do not accept or process untrusted PKCS#12 (.p12/.pfx) files. Restrict PKCS#12 import and parsing to trusted sources, isolate components that must handle PKCS#12 content, and reduce exposure of workflows that ingest user-supplied certificate/key bundles until patched versions are deployed. Where possible, validate provenance of PKCS#12 files before processing.

Remediation

Patch, then assume compromise.

Upgrade OpenSSL to a fixed release that includes the PKCS#12 ASN1_TYPE validation fix. The provided content indicates fixes were released in OpenSSL 3.6.1, 3.5.5, 3.4.4, 3.3.6, 3.0.19, and 1.1.1ze. For downstream products, apply the vendor-supplied updates that incorporate these OpenSSL fixes.
PUBLIC EXPLOITS

Exploits

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VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

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VendorProductType
FreebsdFreebsdapplication
OpenSSL Software FoundationOpensslapplication

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Social activity23

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