CVE Vulnerabilities


Use After Free

Published: Nov 16, 2016 | Modified: Jan 19, 2023
CVSS 3.x
CVSS 2.x
9.3 HIGH

The __ext4_journal_stop function in fs/ext4/ext4_jbd2.c in the Linux kernel before 4.3.3 allows local users to gain privileges or cause a denial of service (use-after-free) by leveraging improper access to a certain error field.


Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code.

Affected Software

Name Vendor Start Version End Version
Linux_kernel Linux 3.10.85 (including) 3.12 (excluding)
Linux_kernel Linux 3.12.46 (including) 3.12.52 (excluding)
Linux_kernel Linux 3.14.49 (including) 3.14.59 (excluding)
Linux_kernel Linux 3.18.20 (including) 3.18.54 (excluding)
Linux_kernel Linux 4.1.4 (including) 4.1.15 (excluding)
Linux_kernel Linux 4.2 (including) 4.2.8 (excluding)
Linux_kernel Linux 4.3 (including) 4.3.3 (excluding)
Linux Ubuntu trusty *
Linux Ubuntu trusty/esm *
Linux Ubuntu upstream *
Linux Ubuntu vivid/ubuntu-core *
Linux-armadaxp Ubuntu upstream *
Linux-aws Ubuntu upstream *
Linux-flo Ubuntu trusty *
Linux-flo Ubuntu upstream *
Linux-gke Ubuntu upstream *
Linux-goldfish Ubuntu trusty *
Linux-goldfish Ubuntu upstream *
Linux-grouper Ubuntu trusty *
Linux-grouper Ubuntu upstream *
Linux-hwe Ubuntu upstream *
Linux-hwe-edge Ubuntu upstream *
Linux-linaro-omap Ubuntu precise *
Linux-linaro-omap Ubuntu upstream *
Linux-linaro-shared Ubuntu precise *
Linux-linaro-shared Ubuntu upstream *
Linux-linaro-vexpress Ubuntu precise *
Linux-linaro-vexpress Ubuntu upstream *
Linux-lts-quantal Ubuntu precise *
Linux-lts-quantal Ubuntu upstream *
Linux-lts-raring Ubuntu precise *
Linux-lts-raring Ubuntu upstream *
Linux-lts-saucy Ubuntu precise *
Linux-lts-saucy Ubuntu upstream *
Linux-lts-trusty Ubuntu precise *
Linux-lts-trusty Ubuntu upstream *
Linux-lts-utopic Ubuntu trusty *
Linux-lts-utopic Ubuntu upstream *
Linux-lts-vivid Ubuntu trusty *
Linux-lts-vivid Ubuntu upstream *
Linux-lts-wily Ubuntu trusty *
Linux-lts-wily Ubuntu upstream *
Linux-lts-xenial Ubuntu upstream *
Linux-maguro Ubuntu trusty *
Linux-maguro Ubuntu upstream *
Linux-mako Ubuntu trusty *
Linux-mako Ubuntu upstream *
Linux-manta Ubuntu trusty *
Linux-manta Ubuntu upstream *
Linux-qcm-msm Ubuntu precise *
Linux-qcm-msm Ubuntu upstream *
Linux-raspi2 Ubuntu upstream *
Linux-raspi2 Ubuntu vivid/ubuntu-core *
Linux-snapdragon Ubuntu upstream *
Linux-ti-omap4 Ubuntu upstream *

Extended Description

The use of previously-freed memory can have any number of adverse consequences, ranging from the corruption of valid data to the execution of arbitrary code, depending on the instantiation and timing of the flaw. The simplest way data corruption may occur involves the system’s reuse of the freed memory. Use-after-free errors have two common and sometimes overlapping causes:

In this scenario, the memory in question is allocated to another pointer validly at some point after it has been freed. The original pointer to the freed memory is used again and points to somewhere within the new allocation. As the data is changed, it corrupts the validly used memory; this induces undefined behavior in the process. If the newly allocated data happens to hold a class, in C++ for example, various function pointers may be scattered within the heap data. If one of these function pointers is overwritten with an address to valid shellcode, execution of arbitrary code can be achieved.

Potential Mitigations