CVE-2026-48065 Details
Description
pam_usb provides hardware authentication for Linux using ordinary removable media. Prior to 0.9.1, src/conf.c allocates heap memory proportional to n_devices, a count derived from libxml2 XPath evaluation of the config file, without first enforcing an upper bound. On 32-bit targets (armv7l, i686 -- both listed in the project Makefile), the multiplication n_devices * sizeof(t_pusb_device) wraps around size_t, causing xmalloc() to receive a very small size. Because xmalloc() only calls abort() on NULL return, a small-but-non-NULL allocation is accepted, and subsequent array writes overflow the heap. This vulnerability is fixed in 0.9.1.
A heap-based buffer overflow vulnerability has been identified in pam_usb versions prior to 0.9.1. The issue arises in src/conf.c, where heap memory is allocated based on n_devices, a count obtained from libxml2 XPath evaluation of the configuration file. This allocation is made without enforcing an upper limit, allowing for integer overflow on 32-bit targets (armv7l, i686). The overflow occurs when n_devices, multiplied by the size of a device structure, exceeds the maximum value representable by size_t, leading to a small allocation that can be exploited to overflow the heap. The vulnerability requires write access to the configuration file, typically owned by root and readable only by the owner, to be exploited during authentication.
Users can upgrade to pam_usb version 0.9.1 or later, where this vulnerability has been fixed.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed May 27, 2026CISA-ADP
Assessed May 28, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/mcdope/pam_usb/issues/352 | [email protected] | ExploitIssue TrackingTechnical DescriptionVendor |
| https://github.com/mcdope/pam_usb/issues/55 | [email protected] | Issue TrackingVendor |
| https://github.com/mcdope/pam_usb/security/advisories/GHSA-24mw-m2vf-36vp | [email protected] | AdvisoryRemedySource CodeVendor |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-122 | Heap-based Buffer Overflow | [email protected] |
| CWE-190 | Integer Overflow or Wraparound | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| pam_usb | <= 0.9.0 (semver) |
CPE
Remediation
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Change History
3 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| May 27, 2026 | New CVE Received | [email protected] |