OpenSSL up to 3.4.5/3.5.6/3.6.2/4.0.0 integrity check

Summaryinfo

A vulnerability was found in OpenSSL up to 3.4.5/3.5.6/3.6.2/4.0.0. It has been rated as problematic. Affected by this issue is some unknown functionality. Performing a manipulation results in integrity check. This vulnerability is cataloged as CVE-2026-34181. It is possible to initiate the attack remotely. There is no exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability, which was classified as problematic, was found in OpenSSL up to 3.4.5/3.5.6/3.6.2/4.0.0. This affects an unknown function. The manipulation with an unknown input leads to a integrity check vulnerability. CWE is classifying the issue as CWE-354. The product does not validate or incorrectly validates the integrity check values or "checksums" of a message. This may prevent it from detecting if the data has been modified or corrupted in transmission. This is going to have an impact on integrity. The summary by CVE is:

Issue 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.

It is possible to read the advisory at openssl-library.org. This vulnerability is uniquely identified as CVE-2026-34181 since 03/26/2026. The exploitability is told to be difficult. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 06/09/2026).

Upgrading to version 3.4.6, 3.5.7, 3.6.3 or 4.0.1 eliminates this vulnerability.

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Productinfo

Type

• Network Encryption Software

Name

• OpenSSL

Version

• 3.4.0
• 3.4.1
• 3.4.2
• 3.4.3
• 3.4.4
• 3.4.5
• 3.5.0
• 3.5.1
• 3.5.2
• 3.5.3
• 3.5.4
• 3.5.5
• 3.5.6
• 3.6.0
• 3.6.1
• 3.6.2
• 4.0

License

• open-source

Website

• Product: https://www.openssl.org/

CPE 2.3info

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CPE 2.2info

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