CVE-2026-47271: CWE-476: NULL Pointer Dereference in mcdope pam_usb
CVE-2026-47271 is a NULL pointer dereference vulnerability in pam_usb versions prior to 0.9.0. The issue arises because out-of-memory guards implemented with assert() are compiled out in release builds, causing allocation functions to return NULL without checks. This leads to a crash in the PAM module when memory allocation fails, resulting in a local denial-of-service by preventing authentication via sudo or login. The vulnerability is fixed in version 0.9.0.
AI Analysis
Technical Summary
The vulnerability in pam_usb (before version 0.9.0) stems from the removal of assert-based out-of-memory guards in memory allocation functions (xmalloc, xrealloc, xstrdup) due to the NDEBUG macro being defined in release builds. Without these guards, these functions return NULL on allocation failure, but the codebase does not check for NULL before dereferencing, causing a NULL pointer dereference crash. This crash in the PAM module disrupts authentication processes such as sudo and login, creating a local denial-of-service condition. The issue is resolved in pam_usb version 0.9.0.
Potential Impact
An attacker capable of inducing memory pressure at authentication time can cause the pam_usb module to crash due to NULL pointer dereference. This crash prevents successful authentication via sudo or login for all users during the crash period, resulting in a local denial-of-service. There is no impact on confidentiality or integrity, only availability is affected.
Mitigation Recommendations
This vulnerability is fixed in pam_usb version 0.9.0. Users and administrators should upgrade to version 0.9.0 or later to remediate this issue. Since no official patch link or advisory is provided, verify the upgrade availability from the vendor or trusted repositories. Until upgraded, be aware that inducing memory pressure can cause authentication failures.
CVE-2026-47271: CWE-476: NULL Pointer Dereference in mcdope pam_usb
Description
CVE-2026-47271 is a NULL pointer dereference vulnerability in pam_usb versions prior to 0.9.0. The issue arises because out-of-memory guards implemented with assert() are compiled out in release builds, causing allocation functions to return NULL without checks. This leads to a crash in the PAM module when memory allocation fails, resulting in a local denial-of-service by preventing authentication via sudo or login. The vulnerability is fixed in version 0.9.0.
CVSS v3.1
Score 5.1medium
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in pam_usb (before version 0.9.0) stems from the removal of assert-based out-of-memory guards in memory allocation functions (xmalloc, xrealloc, xstrdup) due to the NDEBUG macro being defined in release builds. Without these guards, these functions return NULL on allocation failure, but the codebase does not check for NULL before dereferencing, causing a NULL pointer dereference crash. This crash in the PAM module disrupts authentication processes such as sudo and login, creating a local denial-of-service condition. The issue is resolved in pam_usb version 0.9.0.
Potential Impact
An attacker capable of inducing memory pressure at authentication time can cause the pam_usb module to crash due to NULL pointer dereference. This crash prevents successful authentication via sudo or login for all users during the crash period, resulting in a local denial-of-service. There is no impact on confidentiality or integrity, only availability is affected.
Mitigation Recommendations
This vulnerability is fixed in pam_usb version 0.9.0. Users and administrators should upgrade to version 0.9.0 or later to remediate this issue. Since no official patch link or advisory is provided, verify the upgrade availability from the vendor or trusted repositories. Until upgraded, be aware that inducing memory pressure can cause authentication failures.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-05-18T23:03:37.229Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a17519de29bf47b50e771a1
Added to database: 05/27/2026, 20:18:37 UTC
Last enriched: 06/03/2026, 20:53:11 UTC
Last updated: 07/31/2026, 19:22:59 UTC
Views: 37
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