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Fencer Vulns
medium 6.8

CVE-2026-40253 json

openCryptoki: Memory safety vulnerabilities in BER/DER decoders in asn1.c

published 2026-04-16 6 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-23318

cvss
6.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 5%
public exploits
0
none known

Summary

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.

Patch / fix

  • opencryptoki Debian 13 3.23.0+dfsg-0.3+deb13u1
  • opencryptoki Debian 14 3.27.0-1

debian advisories DEBIAN-CVE-2026-40253

  • opencryptoki Ubuntu 22.04 LTS 3.17.0+dfsg+20220202.b40982e-0ubuntu1.3
  • opencryptoki Ubuntu 24.04 LTS 3.23.0+dfsg-0ubuntu3.1
  • opencryptoki Ubuntu 26.04 LTS 3.26.0+dfsg-0ubuntu1.1

ubuntu advisories UBUNTU-CVE-2026-40253

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • opencryptoki RHEL 9 3.26.0-2.el9_8.2
  • opencryptoki-libs RHEL 9 3.26.0-2.el9_8.2
  • opencryptoki-swtok RHEL 9 3.26.0-2.el9_8.2
  • opencryptoki-ccatok RHEL 9 3.26.0-2.el9_8.2
  • opencryptoki-icatok RHEL 9 3.26.0-2.el9_8.2
  • opencryptoki-ep11tok RHEL 9 3.26.0-2.el9_8.2
  • opencryptoki-icsftok RHEL 9 3.26.0-2.el9_8.2
  • opencryptoki RHEL 10.2 3.26.0-3.el10_2.1

red hat advisories RHSA-2026:36697RHSA-2026:36717RHSA-2026:33519RHSA-2026:28256RHSA-2026:28231RHSA-2026:26352

  • openCryptoki SLE Module for Server Applications 15 SP7 3.26.0-150700.5.17.1
  • openCryptoki SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 3.27.0-160000.1.1
  • openCryptoki SLE Micro 5.4 3.17.0-150400.4.16.1
  • openCryptoki SLES LTSS Extended Security 12 SP5, SLES 12 SP5-LTSS 3.17.0-5.24.1

suse advisories SUSE-SU-2026:2685-2SUSE-SU-2026:2757-1SUSE-SU-2026:2685-1SUSE-SU-2026:22293-1SUSE-SU-2026:22365-1SUSE-SU-2026:2355-1

  • openCryptoki openSUSE Leap 16.0 3.27.0-160000.1.1
  • openCryptoki openSUSE Tumbleweed 3.26.0-6.1

opensuse advisories openSUSE-SU-2026:21059-1openSUSE-SU-2026:10593-1

  • opencryptoki AlmaLinux 10 3.26.0-3.el10_2.1
  • opencryptoki-libs AlmaLinux 10 3.26.0-3.el10_2.1
  • opencryptoki-swtok AlmaLinux 10 3.26.0-3.el10_2.1
  • opencryptoki-ccatok AlmaLinux 10 3.26.0-3.el10_2.1
  • opencryptoki-icatok AlmaLinux 10 3.26.0-3.el10_2.1
  • opencryptoki-ep11tok AlmaLinux 10 3.26.0-3.el10_2.1
  • opencryptoki-icsftok AlmaLinux 10 3.26.0-3.el10_2.1
  • opencryptoki AlmaLinux 9 3.26.0-2.el9_8.2

almalinux advisories ALSA-2026:28231ALSA-2026:28256ALSA-2026:26352

  • opencryptoki Rocky Linux 10 3.26.0-3.el10_2.1
  • opencryptoki Rocky Linux 9 3.26.0-2.el9_8.2
  • opencryptoki Rocky Linux 8 3.22.0-3.el8_10.3

rocky linux advisories RLSA-2026:28231RLSA-2026:28256RLSA-2026:26352

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-40253 updated cvss 6.8

openCryptoki: openCryptoki: Information disclosure and Denial of Service via malformed BER-encoded cryptographic objects

  • Red Hat Enterprise Linux 6 opencryptoki, opencryptoki-libs
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 7 opencryptoki, opencryptoki-libs, opencryptoki-swtok, opencryptoki-ccatok, opencryptoki-icatok, opencryptoki-tpmtok, +2 more
    affected: workaround, no fix available “Fix deferred”
  • Red Hat CodeReady Linux Builder EUS (v.9.6) opencryptoki-devel 3.24.0-5.el9_6.2, opencryptoki-debuginfo 3.24.0-5.el9_6.2, opencryptoki-debugsource 3.24.0-5.el9_6.2, opencryptoki-libs-debuginfo 3.24.0-5.el9_6.2, opencryptoki-swtok-debuginfo 3.24.0-5.el9_6.2, opencryptoki-ccatok-debuginfo 3.24.0-5.el9_6.2, +3 more
    fixed: vendor fix RHSA-2026:36717
  • Red Hat Enterprise Linux BaseOS (v. 8) opencryptoki 3.22.0-3.el8_10.3, opencryptoki-libs 3.22.0-3.el8_10.3, opencryptoki-swtok 3.22.0-3.el8_10.3, opencryptoki-ccatok 3.22.0-3.el8_10.3, opencryptoki-icatok 3.22.0-3.el8_10.3, opencryptoki-tpmtok 3.22.0-3.el8_10.3, +2 more
    fixed: vendor fix RHSA-2026:26352
  • Red Hat Enterprise Linux BaseOS (v. 9) opencryptoki 3.26.0-2.el9_8.2, opencryptoki-libs 3.26.0-2.el9_8.2, opencryptoki-swtok 3.26.0-2.el9_8.2, opencryptoki-ccatok 3.26.0-2.el9_8.2, opencryptoki-icatok 3.26.0-2.el9_8.2, opencryptoki-ep11tok 3.26.0-2.el9_8.2, +1 more
    fixed: vendor fix RHSA-2026:28256
  • Red Hat Enterprise Linux BaseOS (v. 10) opencryptoki 3.26.0-3.el10_2.1, opencryptoki-libs 3.26.0-3.el10_2.1, opencryptoki-swtok 3.26.0-3.el10_2.1, opencryptoki-ccatok 3.26.0-3.el10_2.1, opencryptoki-icatok 3.26.0-3.el10_2.1, opencryptoki-ep11tok 3.26.0-3.el10_2.1, +1 more
    fixed: vendor fix RHSA-2026:28231
  • Red Hat Enterprise Linux BaseOS E4S (v.9.4) opencryptoki 3.22.0-3.el9_4.3, opencryptoki-libs 3.22.0-3.el9_4.3, opencryptoki-swtok 3.22.0-3.el9_4.3, opencryptoki-ccatok 3.22.0-3.el9_4.3, opencryptoki-icatok 3.22.0-3.el9_4.3, opencryptoki-ep11tok 3.22.0-3.el9_4.3, +1 more
    fixed: vendor fix RHSA-2026:33519
  • Red Hat Enterprise Linux BaseOS EUS (v. 10.0) opencryptoki 3.24.0-6.el10_0.2, opencryptoki-libs 3.24.0-6.el10_0.2, opencryptoki-swtok 3.24.0-6.el10_0.2, opencryptoki-ccatok 3.24.0-6.el10_0.2, opencryptoki-icatok 3.24.0-6.el10_0.2, opencryptoki-ep11tok 3.24.0-6.el10_0.2, +1 more
    fixed: vendor fix RHSA-2026:36697
show 6 more
  • Red Hat Enterprise Linux BaseOS EUS (v.9.6) opencryptoki 3.24.0-5.el9_6.2, opencryptoki-libs 3.24.0-5.el9_6.2, opencryptoki-swtok 3.24.0-5.el9_6.2, opencryptoki-ccatok 3.24.0-5.el9_6.2, opencryptoki-icatok 3.24.0-5.el9_6.2, opencryptoki-ep11tok 3.24.0-5.el9_6.2, +1 more
    fixed: vendor fix RHSA-2026:36717
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) opencryptoki-devel 3.26.0-2.el9_8.2, opencryptoki-debuginfo 3.26.0-2.el9_8.2, opencryptoki-debugsource 3.26.0-2.el9_8.2, opencryptoki-libs-debuginfo 3.26.0-2.el9_8.2, opencryptoki-swtok-debuginfo 3.26.0-2.el9_8.2, opencryptoki-ccatok-debuginfo 3.26.0-2.el9_8.2, +3 more
    fixed: vendor fix RHSA-2026:28256
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) opencryptoki-devel 3.26.0-3.el10_2.1, opencryptoki-debuginfo 3.26.0-3.el10_2.1, opencryptoki-debugsource 3.26.0-3.el10_2.1, opencryptoki-libs-debuginfo 3.26.0-3.el10_2.1, opencryptoki-swtok-debuginfo 3.26.0-3.el10_2.1, opencryptoki-ccatok-debuginfo 3.26.0-3.el10_2.1, +3 more
    fixed: vendor fix RHSA-2026:28231
  • Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) opencryptoki-devel 3.24.0-6.el10_0.2, opencryptoki-debuginfo 3.24.0-6.el10_0.2, opencryptoki-debugsource 3.24.0-6.el10_0.2, opencryptoki-libs-debuginfo 3.24.0-6.el10_0.2, opencryptoki-swtok-debuginfo 3.24.0-6.el10_0.2, opencryptoki-ccatok-debuginfo 3.24.0-6.el10_0.2, +3 more
    fixed: vendor fix RHSA-2026:36697
  • Red Hat Enterprise Linux CRB (v. 8) opencryptoki-devel 3.22.0-3.el8_10.3, opencryptoki-debuginfo 3.22.0-3.el8_10.3, opencryptoki-debugsource 3.22.0-3.el8_10.3, opencryptoki-libs-debuginfo 3.22.0-3.el8_10.3, opencryptoki-swtok-debuginfo 3.22.0-3.el8_10.3, opencryptoki-ccatok-debuginfo 3.22.0-3.el8_10.3, +4 more
    fixed: vendor fix RHSA-2026:26352
  • Red Hat Enterprise Linux 6 libica, openssl-ibmca Red Hat Enterprise Linux 7 libica, openssl-ibmca Red Hat Enterprise Linux 8 libica, openssl-ibmca, openssl-ibmpkcs11 Red Hat Enterprise Linux 9 libica, openssl-ibmca Red Hat Enterprise Linux 10 libica, openssl-ibmca
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
6 mo ago

Exploit prediction

0.16% chance of exploitation in the next 30 days, higher than 5% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/opencryptoki/opencryptoki/security/advisories/GHSA-c9cf-6vr4-wfxm referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 6.8 CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H
NVD 3.1 6.1 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H

Affected products

  • opencryptoki opencryptoki

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.