CVE-2018-12891An issue was discovered in Xen through 4.10.x. Certain PV MMU operations may take a long time to process. For that reason Xen explicitly…
- 6.5MediumCVSS base score
- 0.43%Exploitation in 30 daysEPSS · top 63% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
An issue was discovered in Xen through 4.10.x. Certain PV MMU operations may take a long time to process. For that reason Xen explicitly checks for the need to preempt the current vCPU at certain points. A few rarely taken code paths did bypass such checks. By suitably enforcing the conditions through its own page table contents, a malicious guest may cause such bypasses to be used for an unbounded number of iterations. A malicious or buggy PV guest may cause a Denial of Service (DoS) affecting the entire host. Specifically, it may prevent use of a physical CPU for an indeterminate period of time. All Xen versions from 3.4 onwards are vulnerable. Xen versions 3.3 and earlier are vulnerable to an even wider class of attacks, due to them lacking preemption checks altogether in the affected code paths. Only x86 systems are affected. ARM systems are not affected. Only multi-vCPU x86 PV guests can leverage the vulnerability. x86 HVM or PVH guests as well as x86 single-vCPU PV ones cannot leverage the vulnerability.
Timeline
ID reserved
By mitre
- 6 days later
· 6 days later
Published
- 6 years later
· 6 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| NVDNVD · Modified | 3.0 | Medium6.5 | CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 0.43% · top 63% of all CVEs (12 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.5.
Affected products
n/a
- affected n/a
References
References8
- DSA-4236 (opens in a new tab)vendor-advisoryx_refsource_DEBIANx_transferred
- https://support.citrix.com/article/CTX235748 (opens in a new tab)x_refsource_CONFIRMx_transferred
- GLSA-201810-06 (opens in a new tab)vendor-advisoryx_refsource_GENTOOx_transferred
- [debian-lts-announce] 20181112 [SECURITY] [DLA 1577-1] xen security update (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
- http://xenbits.xen.org/xsa/advisory-264.html (opens in a new tab)x_refsource_CONFIRMx_transferred
- 1041201 (opens in a new tab)vdb-entryx_refsource_SECTRACKx_transferred
- [oss-security] 20180627 Xen Security Advisory 264 (CVE-2018-12891) - preemption checks bypassed in x86 PV MM handling (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
- 104570 (opens in a new tab)vdb-entryx_refsource_BIDx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2018-4844 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2018-12891)Record last updated .