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CVE-2026-48984— pam_usb: xfree() does not call explicit_bzero — sensitive cryptographic material may linger in freed heap

Quick assessment

Affected
mcdope pam_usb
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

mcdope pam_usb是mcdope的认证模块。 mcdope pam_usb 0.9.1及之前版本存在资源管理错误漏洞，该漏洞源于xfree()内存释放函数未在调用free()前清除缓冲区内容，导致释放的堆内存中残留敏感数据（包括一次性填充字节），可能通过释放后重用或堆检查原语恢复填充值或其他认证材料。

CVSS 4.7 · Medium EPSS 0.15% · P3

Possible ATT&CK Techniques 1 AI

T1530 · Data from Cloud Storage

Affected Version Matrix 1

VendorProduct Version RangeStatus
mcdope pam_usb < 0.9.2 affected
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I. Basic Information for CVE-2026-48984

Vulnerability Information
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Vulnerability Title
pam_usb: xfree() does not call explicit_bzero — sensitive cryptographic material may linger in freed heap
Source: CVE Program / CVE List V5
Vulnerability Description
pam_usb provides hardware authentication for Linux using ordinary removable media. In versions 0.9.1 and below, the xfree() memory release helper in calls free() without first zeroing the buffer contents, releasing heap-allocated buffers containing sensitive data — including one-time pad bytes read from disk — without clearing, leaving the sensitive content in freed heap memory until it happens to be overwritten by a subsequent allocation. On a system where a use-after-free condition exists, or where a heap inspection primitive becomes available, this could allow recovery of pad values or other authentication material from freed memory regions. This is a defence-in-depth requirement consistent with prior hardening work in this codebase (GHSA-vx6f-rrqr-j87c applied explicit_bzero to some pad paths; this issue generalises the pattern to the central deallocation helper).
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
编译器移除释放缓冲区的代码
Source: CVE Program / CVE List V5
Vulnerability Title
mcdope pam_usb 资源管理错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
mcdope pam_usb是mcdope的认证模块。 mcdope pam_usb 0.9.1及之前版本存在资源管理错误漏洞，该漏洞源于xfree()内存释放函数未在调用free()前清除缓冲区内容，导致释放的堆内存中残留敏感数据（包括一次性填充字节），可能通过释放后重用或堆检查原语恢复填充值或其他认证材料。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
mcdope pam_usb < 0.9.2 -

II. Public POCs for CVE-2026-48984

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III. Intelligence Information for CVE-2026-48984

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Patches & Fixes for CVE-2026-48984 (1)

Vendor Advisories for CVE-2026-48984 (1)

Same Patch Batch · mcdope · 2026-06-18 · 7 CVEs total

CVE-2026-48981 6.7 MEDIUM pam_usb: xmlReadFile flags=0 permits XXE network entity fetching in conf.c
CVE-2026-48980 6.3 MEDIUM pam_usb: getenv() used in PAM context allows environment variable injection into local-che
CVE-2026-48982 5.8 MEDIUM pam_usb: Missing O_EXCL on pad temp file creation allows concurrent update race
CVE-2026-48983 5.8 MEDIUM pam_usb: TOCTOU race condition in pad directory creation allows symlink substitution
CVE-2026-48985 5.5 MEDIUM pam_usb: NULL Dereference Crash in pusb_is_loginctl_local when loginctl Returns Empty Remo
CVE-2026-48986 4.7 MEDIUM pam_usb: Infinite loop DoS in process-tree walk when parent process exits during authentic

IV. Related Vulnerabilities

Same product: pam_usb
Same vendor: mcdope
Same weakness: CWE-14

V. Comments for CVE-2026-48984

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