CVE-2019-18425
What it is
An issue was discovered in Xen through 4.12.x allowing 32-bit PV guest OS users to gain guest OS privileges by installing and using descriptors. There is missing descriptor table limit checking in x86 PV emulation. When emulating certain PV guest operations, descriptor table accesses are performed by the emulating code. Such accesses should respect the guest specified limits, unless otherwise guaranteed to fail in such a case. Without this, emulation of 32-bit guest user mode calls through call gates would allow guest user mode to install and then use descriptors of their choice, as long as the guest kernel did not itself install an LDT. (Most OSes don't install any LDT by default). 32-bit PV guest user mode can elevate its privileges to that of the guest kernel. Xen versions from at least 3.2 onwards are affected. Only 32-bit PV guest user mode can leverage this vulnerability. HVM, PVH, as well as 64-bit PV guests cannot leverage this vulnerability. Arm systems are unaffected.
At a glance
- Exploitability
- Can be exploited over the network without logging in. High risk of data exposure, data tampering, service disruption.
- Exploit odds
- 2.5% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 2.5% in the next 30 days (EPSS).
- Severity: 9.8 CRITICAL (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 2.5% · EPSS, next 30 days
- Weakness
- CWE-269 · Improper privilege management
- Record status
- Modified
Affected
- Xen ≤ 4.12.1
- Debian Linux 9.0
- Debian Linux 10.0
- Fedoraproject Fedora 29
- Fedoraproject Fedora 30
- Fedoraproject Fedora 31
- Opensuse Leap 15.0
Attack profile CVSS 3.1 · 9.8
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2019-18425.md and follow it. Check whether this project is affected by CVE-2019-18425. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
References
- http://lists.opensuse.org/opensuse-security-announce/2019-11/msg00037.html
- http://www.openwall.com/lists/oss-security/2019/10/31/2
- http://xenbits.xen.org/xsa/advisory-298.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2BQKX7M2RHCWDBKNPX4KEBI3MJIH6AYZ/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/I5WWPW4BSZDDW7VHU427XTVXV7ROOFFW/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IZYATWNUGHRBG6I3TC24YHP5Y3J7I6KH/
- https://seclists.org/bugtraq/2020/Jan/21
- https://security.gentoo.org/glsa/202003-56
- https://www.debian.org/security/2020/dsa-4602
- http://lists.opensuse.org/opensuse-security-announce/2019-11/msg00037.html
- http://www.openwall.com/lists/oss-security/2019/10/31/2
- http://xenbits.xen.org/xsa/advisory-298.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2BQKX7M2RHCWDBKNPX4KEBI3MJIH6AYZ/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/I5WWPW4BSZDDW7VHU427XTVXV7ROOFFW/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IZYATWNUGHRBG6I3TC24YHP5Y3J7I6KH/
- https://seclists.org/bugtraq/2020/Jan/21
- https://security.gentoo.org/glsa/202003-56
- https://www.debian.org/security/2020/dsa-4602