Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessObtain local shell as unprivileged user
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ExploitPoll /proc and process table during clevis decrypt
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ExecutionCapture token PIN from pkcs11-tool argv
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ImpactReuse PIN to unlock PKCS#11 token
Vulnerability Assessment
| Weakness |
CWE
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| Exploitation Conditions | Exploitation requires that the host actually uses the clevis PKCS#11 pin (clevis-decrypt-pkcs11), that a decryption operation invoking pkcs11-tool occurs while the attacker is present, and that the attacker is an already-logged-in local user able to read the process table or /proc/<pid>/cmdline. Limiting factors: no remote vector (local access only), authenticated low-privileged access needed, the PKCS#11 pin must be configured (a non-default, specialized clevis binding rather than the common Tang/TPM2 pins), and the attacker must win a timing race against the short-lived pkcs11-tool process, which is why attack complexity is high. |
| Impact | This is a genuine but low-urgency issue. The provided CVSS 3.1 vector (AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N, base 4.7/Medium) tells a consistent story: exploitation requires local access (AV:L), an already-authenticated low-privileged user (PR:L), and high attack complexity (AC:H) because the attacker must observe the process table or /proc during the brief window in which clevis-decrypt-pkcs11 invokes pkcs11-tool. No EPSS score, SSVC decision, KEV listing, or POC reference was supplied in the input, so exploitation-probability and automatability signals are simply absent rather than conflicting - their absence should not be read as low risk, but nothing here elevates it either. There is no public exploit identified at time of analysis and no evidence of active exploitation. The one notable tension is that the impact is rated C:H despite the flaw being pure information disclosure (CWE-214) of a PKCS#11 token PIN: C:H is defensible because the leaked PIN can unlock the cryptographic token and thus the data it protects, but defenders should recognize that the direct bug only discloses a secret rather than granting code execution. Net: a real defect worth patching during normal maintenance, not an emergency, given the local-only, timing-dependent, authenticated prerequisites. |
| Exploit ScenarioDerived | A local unprivileged user with shell access on a RHEL or OpenShift host that uses the clevis PKCS#11 pin repeatedly samples the process listing (ps) or reads /proc/<pid>/cmdline while an automated LUKS/clevis decryption runs, capturing the PKCS#11 token PIN passed as a command-line argument to pkcs11-tool. The attacker then reuses that PIN to unlock the token and access the protected key material. No public exploit is identified, and the high attack complexity reflects the need to race the short-lived invocation window. |
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Alert meAnalysisAIv1 – Oct 14, 2026
Local information disclosure in Red Hat Clevis's PKCS#11 pin lets an already-logged-in, low-privileged local user capture the PKCS#11 token PIN that clevis-decrypt-pkcs11 passes as a command-line argument to pkcs11-tool, from where it is readable through process listing or /proc/<pid>/cmdline. The issue affects Clevis as shipped with Red Hat Enterprise Linux 7, 8, 9 and 10 as well as Red Hat OpenShift Container Platform 4, and carries a CVSS 3.1 base score of 4.7 (AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N), reflecting high confidentiality impact but a local-only, high-complexity attack requiring a non-default configuration. Exploitation requires the PKCS#11 pin to be configured, a decryption operation to be in flight at the same moment, and the attacker to win a timing race against the short-lived pkcs11-tool process; no public exploit code and no confirmed active exploitation (not in CISA KEV) have been identified at time of analysis.
RemediationAI
No vendor-released patch identified at time of analysis; Red Hat is tracking the issue at https://access.redhat.com/security/cve/CVE-2026-109971 and https://bugzilla.redhat.com/show_bug.cgi?id=2550363, and fixed clevis packages should be applied to RHEL 7/8/9/10 and OpenShift 4 hosts as soon as they appear (watch the advisory and Bugzilla for the errata version). Until then, the most effective mitigation is to stop using the PKCS#11 pin on multi-user hosts: rebind the volume with a Tang or TPM2 pin where policy allows, which removes the pkcs11-tool invocation entirely but changes the trust root and requires re-encryption/rebinding. If PKCS#11 must remain in use, patch the local clevis-decrypt-pkcs11 script to deliver the PIN through a protected channel, for example by reading it from a mode-0600 PIN file and using pkcs11-tool's --pin-source option or by feeding it via stdin, accepting that this is an unsupported local modification which will be overwritten by package updates and must be re-applied. Restrict interactive shell access on hosts with clevis PKCS#11 bindings so that only trusted administrators can log in, and consider mounting /proc with hidepid=2 to prevent unprivileged users from reading other processes' command lines, understanding that hidepid can break monitoring, inventory and container tooling on the host. Because the PIN may already have been exposed to any local user present during past decrypts, rotate the PKCS#11 token PIN after applying the fix, and audit local accounts and SSH access on affected RHEL and OpenShift nodes for signs of unauthorized interactive sessions.
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Technical ContextAI · show details
Clevis is Red Hat's pluggable framework for automated decryption, used to bind LUKS volumes and other secrets to a decryption policy through interchangeable 'pins' such as Tang, TPM2, SSS and PKCS#11. The PKCS#11 pin is the specialized binding that unlocks data with a key stored on a PKCS#11 token (hardware HSM, smart card or software token), and clevis-decrypt-pkcs11 implements it by shelling out to OpenSC's pkcs11-tool. The flaw is that the token PIN is supplied as a plain command-line argument, so it lands in the process's argv and becomes observable to any local process owned by another user that can read the process table or /proc/<pid>/cmdline. This is the classic CWE-214 (Invocation of Process Using Visible Sensitive Information) pattern, the same root-cause class as secrets placed in ps-visible command lines or environment variables; pkcs11-tool itself supports safer delivery mechanisms such as --pin-source or a restricted PIN file, which the script does not use in affected builds. The CPE inventory (red_hat_red_hat_enterprise_linux_7 through _10, plus red_hat_red_hat_openshift_container_platform_4) confirms the flaw ships in the clevis packages across every currently supported RHEL stream and in OpenShift Container Platform 4 nodes, whose host users inherit the same local exposure. There is no network attack surface: the vector is strictly local, requires an authenticated low-privileged account, and is complicated by the need to catch the short-lived pkcs11-tool invocation while a legitimate clevis decrypt is running.
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Severity by source
AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
Local authenticated user must race the brief pkcs11-tool invocation to read the PIN from /proc, so AV:L/AC:H/PR:L; leaked token PIN gives C:H with no integrity or availability impact.
Primary rating from Vendor (redhat).
CVSS VectorVendor: redhat
DescriptionCVE.org
A flaw was found in the clevis PKCS#11 pin. The clevis-decrypt-pkcs11 script passes the PKCS#11 token PIN as a command-line argument to pkcs11-tool, making it visible to any local user through process listing or the /proc filesystem.
Threat Intelligence Overview
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.
Affected Products (CPE)CVE.org
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