CVE Intelligence
Unknown

CVE-2026-98918 — mm/damon/ops-common: use a page-aligned address in damon_ptep_mkold()

In the Linux kernel, the following vulnerability has been resolved: mm/damon/ops-common: use a page-aligned address in damon_ptep_mkold() __damon_va_prepare_access_check() picks a random byte address within the region and stores it in r->sampling_addr. damon_va_mkold() passes it into a page table walk, which hands it to damon_ptep_mkold() as the address of the page to sample: damon_va_mkold(mm, r->sampling_addr) damon_va_walk_page_range(mm, addr, addr + 1) damon_mkold_pmd_entry() damon_ptep_mkold(pte, vma, addr) ptep_test_and_clear_young(vma, addr, pte) mmu_notifier_clear_young(mm, addr, addr + PAGE_SIZE) For arm64, before commit 6f0e1142173a ("arm64: mm: support batch clearing of the young flag for large folios"), the contpte helper walked exactly CONT_PTES entries from the aligned-down page table pointer and used @addr only to pass down to each entry, so an unaligned value was harmless: ptep = contpte_align_down(ptep); addr = ALIGN_DOWN(addr, CONT_PTE_SIZE); for (i = 0; i < CONT_PTES; i++, ptep++, addr += PAGE_SIZE) Now the range to walk is derived from @addr instead: end = addr + nr * PAGE_SIZE, rounded up to CONT_PTE_SIZE. For a sample in the last page of a contpte block, the sub-page offset puts end just past the block boundary, so the round-up lands a whole block further and the walk clears PTE_AF in CONT_PTES entries beyond the sampled block. For the last block in a page table page, those entries are past the end of that page, so the walk writes into the page that follows. Triggered by the full 7.1/7.2 kernel selftest suite on arm64 (EC2 c/m6g.4xlarge). The kernel sometimes crashes at or shortly after the DAMON test. What the overrun does depends on the page that happens to follow the page table, so there is no single signature. If that page is read-only, the write faults in the sampling path itself: Unable to handle kernel write to read-only memory at virtual address ffff0003c5d2d000 FSC = 0x0f: level 3 permission fault CM = 0, WnR = 1, TnD = 0, TagAccess = 0 CPU: 10 UID: 0 PID: 3487 Comm: kdamond.2 pc : contpte_test_and_clear_young_ptes+0x70/0xc0 lr : damon_ptep_mkold+0x1e8/0x1f8 Call trace: contpte_test_and_clear_young_ptes+0x70/0xc0 (P) damon_mkold_pmd_entry+0x150/0x170 walk_pmd_range+0x110/0x2b0 walk_pud_range+0x10c/0x208 walk_pgd_range+0x134/0x258 __walk_page_range+0x98/0x1b0 walk_page_range_vma_unsafe+0x90/0x148 walk_page_range_vma+0x28/0x40 damon_va_walk_page_range+0x114/0x2b8 damon_va_prepare_access_checks+0xec/0x1a8 kdamond_fn+0x534/0x770 kthread+0x128/0x138 ret_from_fork+0x10/0x20 Otherwise the page is writable, the PTE_AF clearing succeeds silently and the damage only surfaces later, in whatever happened to own the page, so the backtrace is unrelated to DAMON and differs between runs. Pass a page-aligned address to the ptep_test_and_clear_young() call in damon_ptep_mkold(), which is the only place DAMON can reach contpte_test_and_clear_young_ptes() from. Nothing else sees the aligned address, and r->sampling_addr itself is left as is, so the sampling and region bookkeeping semantics are unchanged.

Published Oct 23, 2026 · Updated Oct 23, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: Linux

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 0.2% (30-day exploitation probability)+1

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
0.16%
ahead of 5% of scored CVEs · Oct 30, 2026
Affects
Linux
Linux
CVSS base
—
Score not published yet.

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Linux Linux).
  2. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  3. Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Linux Linux ≥ 6f0e1142173a54b8a18c59fc3cbae3b31ee423d9 and < d5208de0799c506d3315b6f96d034c38e4509dbb≥ 6f0e1142173a54b8a18c59fc3cbae3b31ee423d9 and < f166586f74dd5d9cbadaabf86ef81c8ddf6cafa7version 7.0 Vulnerable CVE Program (cve.org) e CISA ADP

EPSS over time FIRST

Oct 24, 2026 → Oct 30, 2026 · 7 reading(s) · max 0.20%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Not enough vector or weakness data: use the affected application’s logs as a starting point.
application logs

Timeline

What happened to this CVE, newest first.

  • 2026
  • Record published
    Oct 23, 2026
  • Affected products added · linux/linux
    Oct 23, 2026 · CVE Program (cve.org) e CISA ADP
  • Source status changed · → Received
    Oct 23, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 23, 2026 · Alertas do Telegram
  • CVE published
    Oct 23, 2026 · Linux

Source activity

Repeated readings are counted rather than listed.

  • 1× References added · Oct 23, 2026 – Oct 23, 2026
  • 1× Official description updated · Oct 23, 2026 – Oct 23, 2026

References

2 on the record

Elsewhere on this site

Linux
every CVE for this vendor

Related CVEs (same products)

  • CVE-2026-99216 Drivers: hv: Don't reset VMBus connection state on error/exit paths 3d
  • CVE-2026-99215 power: supply: core: prevent unregistering a power supply while a callback runs 3d
  • CVE-2026-99207 scsi: target: Disable interrupts while holding delayed_cmd_lock 3d
  • CVE-2026-99208 drm/xe/oa: Zero OA buffer at allocation 3d
  • CVE-2026-99209 drm/xe: skip eviction of a BO with no resource 3d
  • CVE-2026-99210 accel/rocket: clear rdev on device init failure 3d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No CVSS score published by NVD, the CNA, CISA or GitHub so far.
  • No fixed version, patch or mitigation documented.
  • No CISA SSVC assessment.
  • No CWE classification.
  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-98918 is "mm/damon/ops-common: use a page-aligned address in damon_ptep_mkold()", rated Unknown. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. EPSS 0.16% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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