CVE-2026-48066
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedpam_usb provides hardware authentication for Linux using ordinary removable media. Prior to 0.9.1, src/log.c contains a process-wide static pointer that is written on every PAM invocation with the address of a stack-local variable. This violates the PAM re-entrancy requirement and creates a data race when the PAM stack is invoked concurrently from multiple threads. This vulnerability is fixed in 0.9.1.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidencepam_usb versions before 0.9.1 have a dangling pointer vulnerability in src/log.c where a process-wide static pointer is repeatedly assigned the address of a stack-local variable. When PAM stack invocations occur concurrently from multiple threads, this creates a data race and potential use-after-free condition as the stack variable goes out of scope while the static pointer still references it.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Local
- Complexity
- High
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- Low
- Availability
- High
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify pam_usb installation and versionRun 'rpm -qa | grep -i pam_usb' on RHEL/CentOS, or 'dpkg -l | grep -i pam-usb' on Debian/Ubuntu, or check for the pam_usb.so PAM module in /lib/security/ or /lib64/security/. Use 'strings' or 'rpm -qi' on the found package to get the exact version number.Affected if The installed version is below 0.9.1 (e.g., 0.9.0, 0.8.x, or any version prior to 0.9.1).
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Check for concurrent PAM authentication capabilityReview the PAM configuration in /etc/pam.d/ to determine if pam_usb is configured for services that may be invoked concurrently (such as login, sshd, sudo, or graphical session managers). Check system documentation or PAM module usage to confirm multi-threaded or multi-process access to PAM stack.Affected if The pam_usb module is loaded in a PAM stack that can be triggered by multiple concurrent authentication requests (e.g., sshd with multiple connections, system services handling parallel requests).
A system is affected if pam_usb version is below 0.9.1 AND the pam_usb module is in use within a PAM configuration that can experience concurrent authentication requests, enabling the data race condition in src/log.c.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scopedUpgrade pam_usb to version 0.9.1 or later. If upgrading is not immediately feasible, avoid concurrent PAM authentication requests until the patch can be applied.
pam_usb version 0.9.1
- 1. Check the current installed version of pam_usb on the system using the package manager or by querying the PAM module.
- 2. If the installed version is prior to 0.9.1, upgrade to version 0.9.1 or later.
- 3. After upgrading, verify that the new version is loaded correctly by the PAM subsystem.
- 4. Test the authentication functionality to ensure pam_usb continues to work as expected after the upgrade.
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation3.0 h
- Implementation2.0 h
- Testing6.0 h
- Review / QA3.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,840.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-48066 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-48066 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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