Bug 2344665 (CVE-2025-24031)

Summary: CVE-2025-24031 pam_pkcs11: PAM-PKCS#11 vulnerable to segmentation fault on ctrl-c/ctrl-d when asked for PIN
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: medium    
Version: unspecifiedKeywords: Security
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OS: Linux   
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A flaw was found in the pam_pkcs11 Linux-PAM login module. A segmentation fault condition may be triggered in certain versions when a user presses ctrl-c/ctrl-d when asked for a PIN. When a user does not enter a PIN, `pam_get_pwd` will never initialize the password buffer pointer, and `cleanse` will try to dereference an uninitialized pointer. This issue may lead to an application crash or other unintended behavior.
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Description OSIDB Bzimport 2025-02-10 16:01:06 UTC 
PAM-PKCS#11 is a Linux-PAM login module that allows a X.509 certificate based user login. In versions 0.6.12 and prior, the pam_pkcs11 module segfaults when a user presses ctrl-c/ctrl-d when they are asked for a PIN. When a user enters no PIN at all, `pam_get_pwd` will never initialize the password buffer pointer and as such `cleanse` will try to dereference an uninitialized pointer. On my system this pointer happens to have the value 3 most of the time when running sudo and as such it will segfault. The most likely impact to a system affected by this issue is an availability impact due to a daemon that uses PAM crashing. As of time of publication, a patch for the issue is unavailable.