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CVE-2026-64533

fs/ntfs3: validate lcns_follow in log_replay conversion

No known exploitation. EPSS puts it in the 3rd percentile. Fixed versions are out.

CVSS 3.17.8HighEPSS percentile3rd0.1% chance in 30 daysCISA KEVNot listedNo confirmed exploitation
No public exploit knownFix1 product4 fixed builds listed below
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OpenVAS · 26 checks

e.g. OID 1.3.6.1.4.1.25623.1.0.157823

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Published Updated Sources: CVE.org, NVD

NVD CVE.org

What to do

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  • LinuxAffected: ≥ b46acd6a6a627d876898e1c84d3f84902264b445, < ca343a99806b4fc8e27c48f08be3445c5fcd1445Upgrade to: ca343a99806b4fc8e27c48f08be3445c5fcd1445Affected: ≥ b46acd6a6a627d876898e1c84d3f84902264b445, < ddfc8683e1a627dbf1b83bacf8961443dd654258Upgrade to: ddfc8683e1a627dbf1b83bacf8961443dd654258Affected: ≥ b46acd6a6a627d876898e1c84d3f84902264b445, < 57c071e2c4f30b9c6f5aacb6679aab1269fbae99Upgrade to: 57c071e2c4f30b9c6f5aacb6679aab1269fbae99Affected: ≥ b46acd6a6a627d876898e1c84d3f84902264b445, < 159f694d682e4215b3822ae31ed3a4631628fe55Upgrade to: 159f694d682e4215b3822ae31ed3a4631628fe55 + 3 more branchesStated by: CVE record

Versions as the sources state them. Full version matrix after sign-in

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What it is

From the CVE record

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]

In plain language

No plain-language summary for this CVE yet.

Exploitation

Where each signal puts this CVE on the scale from published to confirmed exploited.

EPSS3rd
CISA KEV

Not in the catalog. CISA has not confirmed exploitation.

Public exploits

No public exploit or proof of concept found in the sources we track.

EPSS

0.1% chance of exploitation activity in the next 30 days, which ranks it in the 3rd percentile of scored CVEs.

Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.

Lifecycle

10 events over 99 days, from the signal feeds we watch.

  1. Record updated
  2. Record updated
  3. Record updated
  4. Record updated
  5. OpenVAS check added
  6. Record updated

Affected products

Technical detail

CVSS 3.1 vector

Open in the CVSS calculator

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Scored 7.8 by NVD.

How it is reached

  • Attack Vector LocalRequires local access to the vulnerable system (e.g. local login, malicious file)
  • Attack Complexity LowNo special conditions — the attack can be reliably reproduced
  • Privileges Required NoneNo authentication required — anyone can exploit this
  • User Interaction RequiredA user must click a link, open a file, or perform some action

Scope

  • Scope UnchangedImpact is limited to the vulnerable component itself

Impact if exploited

  • Confidentiality HighTotal information disclosure — all data in the component is compromised
  • Integrity HighTotal loss of integrity — attacker can modify any data in the component
  • Availability HighTotal denial of service — the component is completely unavailable

Weaknesses

ATT&CK techniques

Mapped from the weaknesses above (CWE to ATT&CK), not observed in attacks.

Sources

References in the record

And 4 more references. See all after sign-in

In the news

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