Answer in brief
CVE-2026-64667 records a Medium severity (CVSS 4.4) vulnerability in pam_usb: Heap out-of-bounds read in pusb_get_tty_from_display_server cmdline scan. The current sources do not mark it as known exploited. The current feed maps mcdope/pam_usb (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 4.4. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps mcdope/pam_usb (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| mcdope/pam_usbgeneric | <0.9.3 | 0.9.3 |
Published upstream
Nov 11, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Nov 11, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Nov 11, 2026
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.
Quoted source text, attributed separately from HOL analysis.