CVE-2026-92499

ext4: validate readdir offset before accessing dirent

Products / packages Linux

Published 17/09/2026, 16:10:13 UTC

Severity and exploitation

Not in CISA KEVNo CVSS score

KEV coverage does not rule out exploitation.

KEV checked 14/11/2026, 21:40:35 UTC

Severity

unknown

CVSS measures technical severity, not the likelihood of an attack.

Known exploitation

Not listed in the checked CISA KEV catalog

Absence from CISA KEV does not rule out attacks.

Public exploit

Not established by this record

Missing evidence does not mean no public exploit exists.

Remediation

Fix status not established

No structured fix or guidance is available here. Check the latest publisher advisory.

What this means

The Linux kernel's ext4 file system is vulnerable to a use-after-free error when accessing a corrupted directory, potentially causing a crash. The issue affects Linux kernel versions starting from 2.6.19 up to but not including 6.12.117, 6.18.52, and 7.2.6. An attacker with access to the system would need to create a corrupted directory to exploit this vulnerability.

Summarized by @cf/meta/llama-3.3-70b-instruct-fp8-fast. Verify details against the original sources.

Attack conditions

No attack-condition excerpt has been identified here. Review the full source description and references for authentication, network access, and configuration requirements.

Review supporting sources →

Affected versions

Check the exact model, release, and any platform requirements against your installation.

Linux · Linux

Linux

4 ranges

Linux version evidence

Check a product version

Compare with this publisher’s ranges. This does not inspect your installation.

affected

ac27a0ec112a089f1a5102bc8dffc79c8c815571 → before 094e8139cf5a5e37b363ac984f628359558415e6

git versions

ac27a0ec112a089f1a5102bc8dffc79c8c815571 → before 64d445d40e5ea4c4d4d88880db753b370cb69161

git versions

ac27a0ec112a089f1a5102bc8dffc79c8c815571 → before b4c728577933753180e3e97f08424d5bcaff705e

git versions

ac27a0ec112a089f1a5102bc8dffc79c8c815571 → before bc4b7b0414c33b2c8898eb04386df0d21a13dad8

git versions

Other versions: unaffected

Linux · Linux

Linux

6 ranges

Linux version evidence

Check a product version

Compare with this publisher’s ranges. This does not inspect your installation.

affected

2.6.19

unaffected

0 → before 2.6.19

semver versions

6.12.117 → through 6.12.*

semver versions

6.18.52 → through 6.18.*

semver versions

7.2.6 → through 7.2.*

semver versions

7.3 → through *

original_commit_for_fix versions

Other versions: affected

Automatic dependency matching is unavailable for this record. Use the product evidence and publisher’s instructions to check your installation.

What to do

Compare your installed product and version with the affected versions above. A matching product name alone does not confirm exposure.

No structured fix or remediation guidance is available here. Check the full source description and vendor’s latest advisory for a patch or workaround; do not assume another version is safe.

cve.new guidance unless attributed to a publisher. This page does not inspect your installation.

Public exploit evidence

No public exploit reference is identified in the imported evidence. This is not a claim that no exploit exists.

Original source description

Read the full publisher description

In the Linux kernel, the following vulnerability has been resolved:

ext4: validate readdir offset before accessing dirent

A corrupted directory can trigger the following KASAN report when ext4_readdir() resumes from an invalid position:

BUG: KASAN: use-after-free in __ext4_check_dir_entry+0x5ef/0x820 Read of size 2 at addr ffff88810a646000 by task repro_linear/509

Call Trace: <TASK> dump_stack_lvl+0x53/0x70 print_report+0xd0/0x630 kasan_report+0xce/0x100 __ext4_check_dir_entry+0x5ef/0x820 ext4_readdir+0xcde/0x2b70 iterate_dir+0x1a1/0x520 __x64_sys_getdents64+0x12b/0x220 do_syscall_64+0xf9/0x540 entry_SYSCALL_64_after_hwframe+0x77/0x7f </TASK>

KASAN reports use-after-free because the out-of-bounds access lands in an adjacent freed page. The directory buffer itself is still referenced.

ext4_dir_llseek() invalidates the directory cookie so that ext4_readdir() rescans directory entries from the start of the block. The rescan checks only the lower bound of rec_len before advancing. A corrupted rec_len can therefore place the offset where the block has insufficient space for a complete directory entry. The rescan itself may dereference that truncated entry, or the main loop may pass it to __ext4_check_dir_entry(). The latter reads de->rec_len before validating the range. For example:

block offset 0 4092 4096 |---- de1.rec_len = 4092 -----|----| de2.inode | de2.rec_len ^ OOB, reported as UAF

de2 starts at offset 4092 in this 4 KiB block. Its four-byte inode fits in the block, but its rec_len starts at offset 4096 and crosses the boundary.

The minimum safe length is inode-dependent. Encrypted and casefolded directory entries need eight additional hash bytes, while a valid metadata checksum tail is only 12 bytes.

Cache the metadata checksum feature state and derive the minimum directory entry length from the on-disk format. Use it to bound both the rescan and the offset passed to the main loop. Report an offset in a truncated block tail and skip the remainder of the block, while continuing to accept an offset exactly at the block boundary.

References

4 sources

git.kernel.org/stable/c/094e8139cf5a5e37b363ac984f628359558415e6

Source referenceLinux

git.kernel.org/stable/c/64d445d40e5ea4c4d4d88880db753b370cb69161

Source referenceLinux

git.kernel.org/stable/c/b4c728577933753180e3e97f08424d5bcaff705e

Source referenceLinux

git.kernel.org/stable/c/bc4b7b0414c33b2c8898eb04386df0d21a13dad8

Source referenceLinux

Inside the record

Evidence available

Package identity · not supplied

Version evidence

Remediation guidance · not supplied

Weakness classification · not supplied

Additional publishers · not supplied

Describes the evidence in this view, not whether the product is safe.

Original records

CVE-2026-92499

View the latest unmodified CVE JSON from the official source. It may be newer than this imported page.

cve.new JSON →

Environment requirements

These conditions apply together as specified by the publisher. A matching product name alone does not establish exposure.

Linux · platform conditions

Any condition may hold

Vulnerable product

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

From (inclusive): 2.6.19

After:

Through (inclusive):

Before: 6.12.117

Vulnerable product

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

From (inclusive): 2.6.19

After:

Through (inclusive):

Before: 6.18.52

Vulnerable product

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

From (inclusive): 2.6.19

After:

Through (inclusive):

Before: 7.2.6

Vulnerable product

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

From (inclusive): 2.6.19

After:

Through (inclusive):

Before: 7.3

Applicability preview

[
  {
    "nodes": [
      {
        "operator": "OR",
        "negate": false,
        "cpeMatch": [
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "2.6.19",
            "versionEndExcluding": "6.12.117"
          },
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "2.6.19",
            "versionEndExcluding": "6.18.52"
          },
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "2.6.19",
            "versionEndExcluding": "7.2.6"
          },
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "2.6.19",
            "versionEndExcluding": "7.3"
          }
        ]
      }
    ]
  }
]

Contributing organizations · 1

Linux

Assigning organization

2026-11-10

Timeline

All times UTC

17 Sept 2026, 16:10
Advisory published
Publication date supplied by the source.
10 Nov 2026, 18:15
Source updated
Latest modification date supplied by the source.
10 Nov 2026, 18:24
Last imported by cve.new
Latest catalog import, not the date we first saw this advisory.

What changed

Follow changes

No substantive changes have been recorded here yet. History starts when cve.new observes a change after tracking is enabled; earlier edits are not reconstructed.

Large field values are marked as truncated previews. Original source snapshots remain retained.

Reading the signals

Severity · CVSS: Technical impact and attack conditions. No numeric assessment supplied.
Observed exploitation · KEV: An absent or unavailable KEV listing does not establish that exploitation has not occurred.
Predicted exploitation · EPSS: No EPSS estimate available in this record.

Record identifiers

Aliases: None recorded

Source evidence

Request a correction or dispute

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Find the responsible CNA →Official dispute and escalation process ↗

CVE CVE-2026-92499

Enrichment coverage

NVDNot fully checked

GHSANot fully checked

EUVDNot fully checked

EPSSNot fully checked

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ext4: validate readdir offset before accessing dirent

Severity and exploitation

What this means

Attack conditions

Affected versions

Linux

affected

unaffected

unknown

Linux

affected

unaffected

unknown

What to do

Public exploit evidence

Original source description

References

Inside the record

Evidence available

Original records

Environment requirements

Timeline

Advisory published

Source updated

Last imported by cve.new

What changed