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CVE Record

CVE-2022-49744: mm/uffd: fix pte marker when fork() without fork event

In the Linux kernel, the following vulnerability has been resolved: mm/uffd: fix pte marker when fork() without fork event Patch series "mm: Fixes on pte markers". Patch 1 resolves the syzkiller report from Pengfei. Patch 2 further harden pte markers when used with the recent swapin error markers. The major case is we should persist a swapin error marker after fork(), so child shouldn't read a corrupted page. This patch (of 2): When fork(), dst_vma is not guaranteed to have VM_UFFD_WP even if src may have it and has pte marker installed. The warning is improper along with the comment. The right thing is to inherit the pte marker when needed, or keep the dst pte empty. A vague guess is this happened by an accident when there's the prior patch to introduce src/dst vma into this helper during the uffd-wp feature got developed and I probably messed up in the rebase, since if we replace dst_vma with src_vma the warning & comment it all makes sense too. Hugetlb did exactly the right here (copy_hugetlb_page_range()). Fix the general path. Reproducer: https://github.com/xupengfe/syzkaller_logs/blob/main/221208_115556_copy_page_range/repro.c Bugzilla report: https://bugzilla.kernel.org/show_bug.cgi?id=216808

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

This Linux kernel issue affects memory-management behavior during fork() when userfaultfd write-protection page-table markers are present. The public record does not describe a concrete business impact, CVSS score, or confirmed exploitation. Treat it as a kernel maintenance risk until your Linux vendor maps it to your shipped kernel packages.

Executive priority

Monitor and patch through normal kernel update processes unless vendor guidance raises severity. Escalate priority for shared compute, hosting, CI, or sandboxed workload environments where kernel bugs carry broader blast radius.

Technical view

The fix corrects mm/uffd handling of PTE markers in copy_page_range(). During fork(), dst_vma may not have VM_UFFD_WP even when the source VMA has a marker. The intended behavior is to inherit the marker when needed or leave the destination PTE empty, matching hugetlb behavior.

Likely exposure

Exposure is limited to Linux systems running affected kernel versions identified in the CVE source bundle, including 5.19, 6.1.11, and 6.2. Distribution kernels may differ because of backports, so package-level vendor mapping is required.

Exploitation context

The source bundle links a syzkaller reproducer and a Kernel Bugzilla report. It does not cite active exploitation, weaponized public exploit use, or CISA KEV listing; KEV is false in the provided data.

Researcher notes

Evidence is incomplete for impact classification. The available description focuses on PTE marker inheritance correctness around fork() and userfaultfd write-protect state. Avoid assuming privilege escalation, information disclosure, or denial of service unless a vendor advisory states it.

Mitigation direction

  • Check your Linux vendor advisory for CVE-2022-49744 package mapping.
  • Apply kernel updates containing the cited stable fixes.
  • Prioritize affected kernel lines used on multi-tenant or untrusted-workload hosts.
  • Track distribution backports instead of relying only on upstream version numbers.

Validation and detection

  • Inventory kernel versions across Linux hosts and containers using host kernels.
  • Map installed kernel packages to vendor CVE advisories.
  • Confirm the cited stable fix is present or backported.
  • Review exposure where userfaultfd features may be available to workloads.
Prepared
Confidence
medium
Sources
6

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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CVE-2022-49744 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
0ADP providers
3Source links

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxc56d1b62cce83695823c13e52f73e92eb568c0c1, c56d1b62cce83695823c13e52f73e92eb568c0c1unaffected
LinuxLinux5.19, 0, 6.1.11, 6.2affected
Weakness

CWE details

No CWE listed

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