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VulnerabilityPublished Updated

CVE-2026-64533: Linux kernel · fs/ntfs3: validate lcns_follow in log_replay conversion

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 7.8 High · fixed in ddfc8683e1a627dbf1b83bacf8961443dd654258 : patch Linux kernel soon.

Data as of 26 Oct 2026, 17:30 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 3% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Total control over the software or total information disclosure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in ddfc8683e1a627dbf1b83bacf8961443dd654258, ca343a99806b4fc8e27c48f08be3445c5fcd1445, 159f694d682e4215b3822ae31ed3a4631628fe55 +4
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 27 Jul 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ b46acd6a6a627d876898e1c84d3f84902264b445, < ddfc8683e1a627dbf1b83bacf8961443dd654258
Fixed in
  • ddfc8683e1a627dbf1b83bacf8961443dd654258
LinuxLinuxAffected
  • ≥ b46acd6a6a627d876898e1c84d3f84902264b445, < ca343a99806b4fc8e27c48f08be3445c5fcd1445
Fixed in
  • ca343a99806b4fc8e27c48f08be3445c5fcd1445
LinuxLinuxAffected
  • ≥ b46acd6a6a627d876898e1c84d3f84902264b445, < 159f694d682e4215b3822ae31ed3a4631628fe55
Fixed in
  • 159f694d682e4215b3822ae31ed3a4631628fe55
LinuxLinuxAffected
  • ≥ b46acd6a6a627d876898e1c84d3f84902264b445, < 57c071e2c4f30b9c6f5aacb6679aab1269fbae99
Fixed in
  • 57c071e2c4f30b9c6f5aacb6679aab1269fbae99
LinuxLinuxAffected
  • ≥ b46acd6a6a627d876898e1c84d3f84902264b445, < 32b9f8733feb241627fa5f564b1a99b5cae974c5
Fixed in
  • 32b9f8733feb241627fa5f564b1a99b5cae974c5
LinuxLinuxAffected
  • ≥ b46acd6a6a627d876898e1c84d3f84902264b445, < 7adb38279812c9c06b0e3fa7382f4d7887f3fa2d
Fixed in
  • 7adb38279812c9c06b0e3fa7382f4d7887f3fa2d

Description

In the Linux kernel, the following vulnerability has been resolved: fs/ntfs3: validate lcns_follow in log_replay conversion log_replay() converts DIR_PAGE_ENTRY_32 records into DIR_PAGE_ENTRY records when replaying version 0 restart tables. During this conversion, the memmove() length is derived directly from the on-disk lcns_follow field: memmove(&dp->vcn, &dp0->vcn_low, 2 * sizeof(u64) + le32_to_cpu(dp->lcns_follow) * sizeof(u64)); check_rstbl() validates restart table structure, but does not constrain per-entry lcns_follow values relative to the entry size. A malformed filesystem image can provide an oversized lcns_follow value, causing the conversion memmove() to access memory beyond the bounds of the allocated restart table buffer. The same field is later used to bound iteration over page_lcns[], so validating lcns_follow during conversion also prevents downstream out-of-bounds access from the same malformed metadata. Compute the maximum valid lcns_follow from the already-validated restart table entry size and reject entries that exceed this bound. Reuse the existing t16/t32 scratch variables already declared in log_replay() to avoid introducing new declarations. [almaz.alexandrovich@paragon-software.com: fixed the conflicts]

References

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