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CVE Record

CVE-2022-50675: arm64: mte: Avoid setting PG_mte_tagged if no tags cleared or restored

In the Linux kernel, the following vulnerability has been resolved: arm64: mte: Avoid setting PG_mte_tagged if no tags cleared or restored Prior to commit 69e3b846d8a7 ("arm64: mte: Sync tags for pages where PTE is untagged"), mte_sync_tags() was only called for pte_tagged() entries (those mapped with PROT_MTE). Therefore mte_sync_tags() could safely use test_and_set_bit(PG_mte_tagged, &page->flags) without inadvertently setting PG_mte_tagged on an untagged page. The above commit was required as guests may enable MTE without any control at the stage 2 mapping, nor a PROT_MTE mapping in the VMM. However, the side-effect was that any page with a PTE that looked like swap (or migration) was getting PG_mte_tagged set automatically. A subsequent page copy (e.g. migration) copied the tags to the destination page even if the tags were owned by KASAN. This issue was masked by the page_kasan_tag_reset() call introduced in commit e5b8d9218951 ("arm64: mte: reset the page tag in page->flags"). When this commit was reverted (20794545c146), KASAN started reporting access faults because the overriding tags in a page did not match the original page->flags (with CONFIG_KASAN_HW_TAGS=y): BUG: KASAN: invalid-access in copy_page+0x10/0xd0 arch/arm64/lib/copy_page.S:26 Read at addr f5ff000017f2e000 by task syz-executor.1/2218 Pointer tag: [f5], memory tag: [f2] Move the PG_mte_tagged bit setting from mte_sync_tags() to the actual place where tags are cleared (mte_sync_page_tags()) or restored (mte_restore_tags()).

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 arm64 memory-tagging bug. Under specific MTE-related conditions, page tag state could be marked incorrectly and later copied, causing invalid memory-tag access faults reported by KASAN. Public sources do not provide CVSS, active exploitation, or evidence of broad real-world abuse.

Executive priority

Treat as a targeted kernel maintenance issue, not an emergency based on current evidence. Prioritize patch validation for arm64 fleets, virtualization hosts, test kernels, or environments using MTE/KASAN features.

Technical view

After commit 69e3b846d8a7, mte_sync_tags() could set PG_mte_tagged on pages whose PTEs resembled swap or migration entries. Later page copies could transfer tags not owned by the page, conflicting with KASAN hardware tags. The fix moves PG_mte_tagged setting to the points where tags are actually cleared or restored.

Likely exposure

Exposure appears limited to Linux on arm64 with MTE-related code paths. The CVE record lists Linux kernel versions including 5.14, 5.15.82, 6.0.3, and 6.1 as affected. Confirm against your distribution’s kernel source and vendor advisories.

Exploitation context

No active exploitation is indicated: the CVE is not in KEV, and the provided sources do not describe exploitation. The observed impact in the record is KASAN invalid-access faults in copy_page with CONFIG_KASAN_HW_TAGS=y.

Researcher notes

The record documents a correctness fix in arm64 MTE tag synchronization, not a complete exploit narrative. Severity, CVSS, CWE, and package-level fixed versions are absent. Analysis should focus on commit ancestry, affected stable branches, and whether local builds enable relevant arm64 MTE/KASAN paths.

Mitigation direction

  • Apply a vendor-supported Linux kernel update containing the referenced stable fixes.
  • Prioritize arm64 systems using MTE or hardware-tagged KASAN configurations.
  • If updates are unavailable, consult your Linux vendor for supported mitigation guidance.
  • Track distribution advisories because package-level fixed versions are not provided here.

Validation and detection

  • Inventory arm64 Linux hosts and kernel versions.
  • Check whether kernels include the referenced stable commits.
  • Review kernel configuration for CONFIG_KASAN_HW_TAGS and MTE-related support.
  • Search logs for KASAN invalid-access reports involving copy_page on arm64.
Prepared
Confidence
medium
Sources
5

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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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
0Timeline events
0ADP providers
4Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux69e3b846d8a753f9f279f29531ca56b0f7563ad0, 69e3b846d8a753f9f279f29531ca56b0f7563ad0, 69e3b846d8a753f9f279f29531ca56b0f7563ad0unaffected
LinuxLinux5.14, 0, 5.15.82, 6.0.3, 6.1affected
Weakness

CWE details

No CWE listed

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