CVE-2021-22543: Improper memory handling in Linux KVM
Vulnerability summary
CVE-2021-22543 is a high (CVSS 8.7) vulnerability in debian debian_linux. EPSS estimates a 0.66% chance of exploitation in the next 30 days, higher than 51.6% of scored vulnerabilities. 1 public exploit is recorded.
Public exploit (GitHub, Date unknown)
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 49 · Related 26Timeline
- 26-05-2021PublishedVulnerability first disclosed.
- 16-09-2024Last modifiedVulnerability information updated.
Description
An issue was discovered in Linux: KVM through Improper handling of VM_IO|VM_PFNMAP vmas in KVM can bypass RO checks and can lead to pages being freed while still accessible by the VMM and guest. This allows users with the ability to start and control a VM to read/write random pages of memory and can result in local privilege escalation.
CVSS metrics
8 scores · 5 sources · 3 versions- OSV · UbuntuEcosystem advisory · calculated8.7HighCVSS:4.0/AV:L/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L
- NVDNIST8.7HighCVSS:4.0/AV:L/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- OSV · UbuntuEcosystem advisory · calculated7.8HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HDiffers
- OSV · DebianEcosystem advisory · calculated7.8HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HDiffers
- NVDNIST7.8HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HDiffers
EPSS trend
Probability
0.66%
Chance of exploitation in the next 30 days
Percentile
52%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.66% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
1 foundSecurity Research
Maturity: poc
Weaknesses
CWE · root causeAffected systems
Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.
Ubuntu59 products
- linux< 4.15.0-159.167 | < 5.4.0-84.94
- linux-aws< 4.15.0-1112.119 | < 5.4.0-1056.59
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11< 5.11.0-1017.18~20.04.1
- linux-aws-5.3All versions (No fix recorded)
Redhat21 products
- kernel< 0:2.6.32-754.48.1.el6
- kernel-abi-whitelists< 0:2.6.32-754.48.1.el6
- kernel-debug< 0:2.6.32-754.48.1.el6
- kernel-debug-debuginfo< 0:2.6.32-754.48.1.el6
- kernel-debug-devel< 0:2.6.32-754.48.1.el6
Debian2 products
- linux< 5.10.46-2
- debian_linuxEOL9.0
Fedoraproject1 product
- fedoraEOL33 | 34
Linux1 product
- linux_kernel2021-05-18
Linux kernel1 product
- linux kernel≥ add6a0cd1c5ba51b201e1361b05a5df817083618, < f8be156be163a052a067306417cd0ff679068c97
7 vendors · 95 products
References
32 links- github.com/google/security-research/security/advisories/GHSA-7wq5-phmq-m584X Refsource MISCARTICLEREPORTExploitThird Party Advisory
lists.debian.org/debian-lts-announce/2021/10/msg00010.htmlMailing ListX Refsource MLISTThird Party Advisory- lists.debian.org/debian-lts-announce/2021/12/msg00012.htmlMailing ListX Refsource MLISTThird Party Advisory
