CVE-2019-19768: Use After Free
A use-after-free flaw was found in the Linux kernels implementation of blktrace in the blkaddtrace function. A local attacker with permissions to run block trace instructions against a device can create a situation where the core blocktrace object is used after it is freed. The attacker can pre-groom memory to race this use-after-free to create a condition where memory is corrupted and also likely to be privilege escalation.
The ability to create this condition requires elevated privileges, and it has been decided that this change in Red Hat Enterprise Linux 5 and 6 would risk introducing possible regressions and will not be backported.
Reference: https://bugzilla.kernel.org/showbug.cgi?id=205711
Patch: A patch may be attached to the bugzilla.kernel.org but no patch exists at this time.
Other sources
A use-after-free vulnerability was found in the Linux kernel’s implementation of blktrace in the blkaddtrace function. A local attacker with permissions to run block trace instructions against a device can create a situation where the core blocktrace object is used after it is freed. The attacker can pre-groom memory to race this use-after-free to create a condition where the memory is corrupted and cause privilege escalation. The ability to create this condition requires elevated privileges, and it has been decided that this change in Red Hat Enterprise Linux 5 and 6 would risk introducing possible regressions and will not be backported.
In the Linux kernel 5.4.0-rc2, there is a use-after-free (read) in the blkaddtrace function in kernel/trace/blktrace.c (which is used to fill out a blkiotrace structure and place it in a per-cpu sub-buffer).
— Ubuntu
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
redhat/kernel-rtto a version that resolves this vulnerability.Fixed in 0:3.10.0-1127.8.2.rt56.1103.el7 - Upgrade
Upgrade
redhat/kernelto a version that resolves this vulnerability.Fixed in 0:3.10.0-1127.8.2.el7 - Upgrade
Upgrade
redhat/kernel-altto a version that resolves this vulnerability.Fixed in 0:4.14.0-115.21.2.el7a - Upgrade
Upgrade
redhat/kernelto a version that resolves this vulnerability.Fixed in 0:3.10.0-327.88.1.el7 - Upgrade
Upgrade
redhat/kernelto a version that resolves this vulnerability.Fixed in 0:3.10.0-514.76.1.el7 - Upgrade
Upgrade
redhat/kernelto a version that resolves this vulnerability.Fixed in 0:3.10.0-693.67.1.el7 - Upgrade
Upgrade
redhat/kernelto a version that resolves this vulnerability.Fixed in 0:3.10.0-957.54.1.el7 - Upgrade
Upgrade
redhat/kernelto a version that resolves this vulnerability.Fixed in 0:3.10.0-1062.26.1.el7 - Upgrade
Upgrade
redhat/kernel-rtto a version that resolves this vulnerability.Fixed in 0:4.18.0-193.rt13.51.el8 - Upgrade
Upgrade
redhat/kernelto a version that resolves this vulnerability.Fixed in 0:4.18.0-193.el8 - Upgrade
Upgrade
redhat/kernelto a version that resolves this vulnerability.Fixed in 0:4.18.0-80.18.1.el8_0 - Upgrade
Upgrade
redhat/kernelto a version that resolves this vulnerability.Fixed in 0:4.18.0-147.13.2.el8_1 - Upgrade
Upgrade
redhat/kernel-rtto a version that resolves this vulnerability.Fixed in 1:3.10.0-693.67.1.rt56.665.el6 - Upgrade
Upgrade
debian/linuxto a version that resolves this vulnerability.Fixed in 6.1.176-1Fixed in 6.1.190-1Fixed in 6.12.107-1Fixed in 6.12.115-2Fixed in 7.2.12-1Fixed in 7.2.15-1
Event History
Parent advisories
This vulnerability appears in the following advisories.
Frequently Asked Questions
What is the severity of CVE-2019-19768?
The severity of CVE-2019-19768 is classified as a high vulnerability in the Linux kernel.
How do I fix CVE-2019-19768?
You can fix CVE-2019-19768 by updating to the appropriate patched version of the Linux kernel.
Who is affected by CVE-2019-19768?
CVE-2019-19768 affects users of specific versions of the Linux kernel, particularly those running vulnerable versions on Red Hat systems.
What exploit does CVE-2019-19768 present?
CVE-2019-19768 presents a use-after-free vulnerability that allows local attackers to execute arbitrary code.
Can CVE-2019-19768 be exploited remotely?
CVE-2019-19768 requires local access to the affected system for exploitation, making it less of a remote threat.