FreeBSD VuXML: Documenting security issues in FreeBSD and the FreeBSD Ports Collection

FreeBSD -- Kernel stack disclosure in UFS/FFS

Affected packages
12.0 <= FreeBSD-kernel < 12.0_7
11.2 <= FreeBSD-kernel < 11.2_11


VuXML ID ff82610f-b309-11e9-a87f-a4badb2f4699
Discovery 2019-07-02
Entry 2019-07-30

Problem Description:

A bug causes up to three bytes of kernel stack memory to be written to disk as uninitialized directory entry padding. This data can be viewed by any user with read access to the directory. Additionally, a malicious user with write access to a directory can cause up to 254 bytes of kernel stack memory to be exposed.


Some amount of the kernel stack is disclosed and written out to the filesystem.


CVE Name CVE-2019-5601
FreeBSD Advisory SA-19:10.ufs