PKCS#12 Files with PBMAC1 Are Accepted with Short HMAC Keys

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Summary

CVECVE-2026-34181
StatePUBLISHED
Assigneropenssl
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-06-09 17:17:04 UTC
Updated2026-06-10 08:16:22 UTC
DescriptionIssue Summary: The PKCS#12 file processing fails to perform sufficient input validation for files that use Password-Based Message Authentication Code 1 (PBMAC1) integrity mechanism allowing a certificate and private key forgery. Impact Summary: An attacker impersonating a user can cause a service reading PKCS#12 files to accept forged certificates and private keys with a 1 in 256 probability. If a service accepting PKCS#12 files is using passwords for authenticating the received files, the attacker can create unencrypted PKCS#12 files that use PBMAC1 authentication that specifies an HMAC key of only one byte, allowing them to craft a file that will be accepted with a 1 in 256 probability. That would then cause the service to accept a certificate and private key controlled by the attacker. The FIPS modules are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.

Risk And Classification

Problem Types: CWE-354 | CWE-354 CWE-354 Improper Validation of Integrity Check Value

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA OpenSSL OpenSSL affected 4.0.0 4.0.1 semver Not specified
CNA OpenSSL OpenSSL affected 3.6.0 3.6.3 semver Not specified
CNA OpenSSL OpenSSL affected 3.5.0 3.5.7 semver Not specified
CNA OpenSSL OpenSSL affected 3.4.0 3.4.6 semver Not specified

References

ReferenceSourceLinkTags
github.com/openssl/openssl/commit/0300eb9ddce7a0895bf301a4b0c03a9da2313a0f [email protected] github.com
github.com/openssl/openssl/commit/ec36f2417c4ddd8cabce4b4a60a3d7a7365f2d81 [email protected] github.com
github.com/openssl/openssl/commit/79eb76a937e474bb7610a0a3dc57131dc8dc6610 [email protected] github.com
github.com/openssl/openssl/commit/85dcbb3abaa4878af5c8fbbe11bce708fcf984a7 [email protected] github.com
openssl-library.org/news/secadv/20260609.txt [email protected] openssl-library.org
github.com/openssl/security/commit/0300eb9ddce7a0895bf301a4b0c03a9da2313a0f MITRE github.com
github.com/openssl/security/commit/79eb76a937e474bb7610a0a3dc57131dc8dc6610 MITRE github.com
github.com/openssl/security/commit/85dcbb3abaa4878af5c8fbbe11bce708fcf984a7 MITRE github.com
github.com/openssl/security/commit/ec36f2417c4ddd8cabce4b4a60a3d7a7365f2d81 MITRE github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Pavol Žáčik (Red Hat) (en)

CNA: Alex Gaynor (Anthropic) (en)

CNA: Alicja Kario (Red Hat) (en)

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