CVE-2026-48065: pam_usb: Unchecked integer multiplication before xmalloc() in conf.c allows heap-based buffer overflow on 32-bit targets

Severity: medium (CVSS 6.7 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-27 · updated 2026-10-26
Weakness: CWE-122

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.

Affected products

mcdope pam_usb: before 0.9.1

References

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