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CVE Record

CVE-2022-49992: mm/mprotect: only reference swap pfn page if type match

In the Linux kernel, the following vulnerability has been resolved: mm/mprotect: only reference swap pfn page if type match Yu Zhao reported a bug after the commit "mm/swap: Add swp_offset_pfn() to fetch PFN from swap entry" added a check in swp_offset_pfn() for swap type [1]: kernel BUG at include/linux/swapops.h:117! CPU: 46 PID: 5245 Comm: EventManager_De Tainted: G S O L 6.0.0-dbg-DEV #2 RIP: 0010:pfn_swap_entry_to_page+0x72/0xf0 Code: c6 48 8b 36 48 83 fe ff 74 53 48 01 d1 48 83 c1 08 48 8b 09 f6 c1 01 75 7b 66 90 48 89 c1 48 8b 09 f6 c1 01 74 74 5d c3 eb 9e <0f> 0b 48 ba ff ff ff ff 03 00 00 00 eb ae a9 ff 0f 00 00 75 13 48 RSP: 0018:ffffa59e73fabb80 EFLAGS: 00010282 RAX: 00000000ffffffe8 RBX: 0c00000000000000 RCX: ffffcd5440000000 RDX: 1ffffffffff7a80a RSI: 0000000000000000 RDI: 0c0000000000042b RBP: ffffa59e73fabb80 R08: ffff9965ca6e8bb8 R09: 0000000000000000 R10: ffffffffa5a2f62d R11: 0000030b372e9fff R12: ffff997b79db5738 R13: 000000000000042b R14: 0c0000000000042b R15: 1ffffffffff7a80a FS: 00007f549d1bb700(0000) GS:ffff99d3cf680000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000440d035b3180 CR3: 0000002243176004 CR4: 00000000003706e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> change_pte_range+0x36e/0x880 change_p4d_range+0x2e8/0x670 change_protection_range+0x14e/0x2c0 mprotect_fixup+0x1ee/0x330 do_mprotect_pkey+0x34c/0x440 __x64_sys_mprotect+0x1d/0x30 It triggers because pfn_swap_entry_to_page() could be called upon e.g. a genuine swap entry. Fix it by only calling it when it's a write migration entry where the page* is used. [1] https://lore.kernel.org/lkml/CAOUHufaVC2Za-p8m0aiHw6YkheDcrO-C3wRGixwDS32VTS+k1w@mail.gmail.com/

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

This is a Linux kernel memory-management bug that can trigger a kernel BUG during memory protection changes. The supplied sources show a crash condition, not data theft or remote compromise. Business urgency depends on whether your fleet runs the affected kernel builds.

Executive priority

Treat as a patch-management item with possible availability impact. Escalate if affected kernels are present on critical production systems, but the supplied evidence does not support emergency remote-exploitation handling.

Technical view

The issue is in mm/mprotect handling of swap entries. pfn_swap_entry_to_page() could be called on a genuine swap entry, triggering a BUG in swapops.h. The resolved behavior only references the PFN page when the swap entry type is a write migration entry where page* is used.

Likely exposure

Exposure is limited to systems running affected Linux kernel versions or commit ranges identified by the CVE record. The bundle lists Linux kernel 5.19-related versions and 6.0 entries, but distribution-specific backports are not described.

Exploitation context

The sources describe a kernel crash reached through mprotect call handling. They do not state active exploitation, public exploit availability, privilege requirements, or remote attackability. KEV is false in the provided bundle.

Researcher notes

The evidence is narrow: a Linux kernel fix note, stack trace, affected version metadata, and stable commit references. No CVSS, CWE, exploit status, or distribution package matrix is provided, so exposure validation must rely on local kernel provenance.

Mitigation direction

  • Check your Linux distribution advisory for CVE-2022-49992 coverage.
  • Upgrade kernels to vendor-supported builds containing the referenced stable fixes.
  • Prioritize internet-facing and high-availability systems if they run affected kernels.
  • Avoid direct wrangler-style assumptions; use vendor kernel package metadata for confirmation.

Validation and detection

  • Inventory running kernel versions across Linux hosts.
  • Compare kernel builds against vendor advisories and the referenced stable commits.
  • Review crash logs for BUG traces involving pfn_swap_entry_to_page or mprotect.
  • Confirm patched kernels are actually booted, not only installed.
Prepared
Confidence
medium
Sources
4

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-2022-49992 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
LinuxLinux6c287605fd56466e645693eff3ae7c08fba56e0a, 6c287605fd56466e645693eff3ae7c08fba56e0aunaffected
LinuxLinux5.19, 0, 5.19.6, 6.0affected
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.