CVE-2022-49562: KVM: x86: Use __try_cmpxchg_user() to update guest PTE A/D bits
Vulnerability summary
CVE-2022-49562 is a high (CVSS 7.8) vulnerability in linux. EPSS estimates a 0.28% chance of exploitation in the next 30 days, higher than 20.5% of scored vulnerabilities.
Not severe (CVSS 7.8, local access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 8 · Related 7Timeline
- 26-02-2025PublishedVulnerability first disclosed.
- 05-08-2026Last modifiedVulnerability information updated.
Description
In the Linux kernel, the following vulnerability has been resolved: KVM: x86: Use __try_cmpxchg_user() to update guest PTE A/D bits Use the recently introduced __try_cmpxchg_user() to update guest PTE A/D bits instead of mapping the PTE into kernel address space. The VM_PFNMAP path is broken as it assumes that vm_pgoff is the base pfn of the mapped VMA range, which is conceptually wrong as vm_pgoff is the offset relative to the file and has nothing to do with the pfn. The horrific hack worked for the original use case (backing guest memory with /dev/mem), but leads to accessing "random" pfns for pretty much any other VM_PFNMAP case.
CVSS metrics
4 scores · 4 sources · 1 version- OSV · UbuntuEcosystem advisory · calculated7.8HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HDiffers
- NVDNIST5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HDiffers
EPSS trend
Probability
0.28%
Chance of exploitation in the next 30 days
Percentile
21%
Versus all other CVEs
30-day change
Increase +0.01 pp
From 0.27% on 06-10-2026
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
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeNo weakness data has been published for this record.
Affected systems
Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.
Ubuntu113 products
- linux< 5.15.0-202.212 | All versions (No fix recorded)
- linux-allwinner-5.19All versions (No fix recorded)
- linux-awsAll versions (No fix recorded) | < 5.15.0-1119.126
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11All versions (No fix recorded)
Linux2 products
- linux≥ bd53cb35a3e9adb73a834a36586e9ad80e877767, < 38b888911e8dc89b89d8147cfb1d2dbe6373bf78 | ≥ bd53cb35a3e9adb73a834a36586e9ad80e877767, < 8089e5e1d18402fb8152d6b6815450a36fffa9b0 | ≥ bd53cb35a3e9adb73a834a36586e9ad80e877767, < f122dfe4476890d60b8c679128cd2259ec96a24c | 5.2
- linux_kernel≥ 5.2, < 5.17.13 | ≥ 5.18, < 5.18.2
Debian1 product
- linux< 5.18.2-1
3 vendors · 116 products
