openCryptoki up to 3.26.0 on Linux/AIX asn1.c length out-of-bounds

Summaryinfo

A vulnerability has been found in openCryptoki up to 3.26.0 on Linux/AIX and classified as problematic. The impacted element is the function ber_decode_INTEGER/ber_decode_SEQUENCE/ber_decode_OCTET_STRING/ber_decode_BIT_STRING/ber_decode_CHOICE of the file asn1.c. Performing a manipulation of the argument length results in out-of-bounds. This vulnerability is cataloged as CVE-2026-40253. The attack must be initiated from a local position. There is no exploit available. It is suggested to install a patch to address this issue.

Detailsinfo

A vulnerability, which was classified as problematic, was found in openCryptoki up to 3.26.0 on Linux/AIX. This affects the function ber_decode_INTEGER/ber_decode_SEQUENCE/ber_decode_OCTET_STRING/ber_decode_BIT_STRING/ber_decode_CHOICE of the file asn1.c. The manipulation of the argument length with an unknown input leads to a out-of-bounds vulnerability. CWE is classifying the issue as CWE-125. The product reads data past the end, or before the beginning, of the intended buffer. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

openCryptoki is a PKCS#11 library and provides tooling for Linux and AIX. In versions 3.26.0 and below, the BER/DER decoding functions in the shared common library (asn1.c) accept a raw pointer but no buffer length parameter, and trust attacker-controlled BER length fields without validating them against actual buffer boundaries. All primitive decoders are affected: ber_decode_INTEGER, ber_decode_SEQUENCE, ber_decode_OCTET_STRING, ber_decode_BIT_STRING, and ber_decode_CHOICE. Additionally, ber_decode_INTEGER can produce integer underflows when the encoded length is zero. An attacker supplying a malformed BER-encoded cryptographic object through PKCS#11 operations such as C_CreateObject or C_UnwrapKey, token loading from disk, or remote backend communication can trigger out-of-bounds reads. This affects all token backends (Soft, ICA, CCA, TPM, EP11, ICSF) since the vulnerable code is in the shared common library. A patch is available thorugh commit ed378f463ef73364c89feb0fc923f4dc867332a3.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-40253 since 04/10/2026. The exploitability is told to be easy. An attack has to be approached locally. Technical details are known, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 307346 (Linux Distros Unpatched Vulnerability : CVE-2026-40253), which helps to determine the existence of the flaw in a target environment.

Applying the patch ed378f463ef73364c89feb0fc923f4dc867332a3 is able to eliminate this problem. The bugfix is ready for download at github.com.

The vulnerability is also documented in the databases at CNNVD (CNNVD-202604-3433), Tenable (307346) and CERT Bund (WID-SEC-2026-1957). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Affected

• Red Hat Enterprise Linux
• SUSE Linux
• Oracle Linux
• RESF Rocky Linux

Productinfo

Name

• openCryptoki

Version

• 3.0
• 3.1
• 3.2
• 3.3
• 3.4
• 3.5
• 3.6
• 3.7
• 3.8
• 3.9
• 3.10
• 3.11
• 3.12
• 3.13
• 3.14
• 3.15
• 3.16
• 3.17
• 3.18
• 3.19
• 3.20
• 3.21
• 3.22
• 3.23
• 3.24
• 3.25
• 3.26.0

License

• open-source

Website

• Product: https://github.com/opencryptoki/opencryptoki/

CPE 2.3info

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CPE 2.2info

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Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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