Description
pam_usb provides hardware authentication for Linux using removable media. Prior to version 0.9.3, src/local.c (pusb_get_tty_from_display_server) allocates a 4096-byte cmdline buffer, reads up to 4096 bytes from /proc//cmdline, then replaces every NUL separator with a space. When read(2) returns exactly 4096 bytes for any process the function inspects, the buffer ends without a terminator and the subsequent strstr() calls scan past the allocation boundary. The function is invoked during normal PAM authentication when DISPLAY is set, so the read fires for every process at auth time. Consequences are bounded: strstr output is a Boolean substring match (limited info-disclosure surface) but a hostile heap layout can produce a SIGSEGV that terminates the host PAM process. This issue has been patched in version 0.9.3.
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Remediation
No vendor fix or workaround currently provided.
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References
History
Wed, 11 Nov 2026 04:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | pam_usb provides hardware authentication for Linux using removable media. Prior to version 0.9.3, src/local.c (pusb_get_tty_from_display_server) allocates a 4096-byte cmdline buffer, reads up to 4096 bytes from /proc//cmdline, then replaces every NUL separator with a space. When read(2) returns exactly 4096 bytes for any process the function inspects, the buffer ends without a terminator and the subsequent strstr() calls scan past the allocation boundary. The function is invoked during normal PAM authentication when DISPLAY is set, so the read fires for every process at auth time. Consequences are bounded: strstr output is a Boolean substring match (limited info-disclosure surface) but a hostile heap layout can produce a SIGSEGV that terminates the host PAM process. This issue has been patched in version 0.9.3. | |
| Title | pam_usb: Heap out-of-bounds read in pusb_get_tty_from_display_server cmdline scan | |
| Weaknesses | CWE-125 | |
| References |
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| Metrics |
cvssV3_1
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Subscriptions
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Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-11-11T03:51:59.164Z
Reserved: 2026-07-20T17:12:12.891Z
Link: CVE-2026-64667
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OpenCVE Enrichment
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Weaknesses
-
CWE-125
Out-of-bounds Read