CVE-2026-93813High· 7.8▾ Twilight

In the Linux kernel, the following vulnerability has been resolved: btrfs: tree-checker: validate INODE_REF's namelen [BUG] A crafted btrfs image can trigger the following crash: BUG: unable to handle page fault for address: ffffd1d…

▾ Twilight zone — High severity, or a signal on a lesser flaw

Depth score43/ 100 · Moderate

impact 42.9 · likelihood 0 · exploitation 0

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Proof of concept

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Published

Sep 24, 2026

Updated

Oct 3, 2026

CVSS

7.8

Vendor

Linux

Product

Linux

CWE

—

Depth score

43 · Moderate

EPSS

0.13% · p3

Platforms

—

Source

NVD

Vector

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

EPSS history

Exploit-prediction probability, daily snapshots since Sep 26.

0.1% → 0.1%

Timeline

Disclosure to exploitation, from the record and what we observed since indexing it.

6 events · 10 days

Sep 24, 2026Published
Disclosed via NVD
Sep 25, 2026CVSS changed
— → 7.8
Sep 25, 2026Severity changed
none → high
Sep 26, 2026EPSS first tracked
0.1%
Oct 3, 2026Record revised
Last analysed / modified upstream
Oct 4, 2026EPSS peak
0.1% → 0.1%

Linux #nvd #cve.org

Affected

Linux >= 2ede0daf01549cecf4bb0962c46dc47382047523 < 60078a3e25c09d9d8fba828b0d81bb33e449a1b2
Linux >= 2ede0daf01549cecf4bb0962c46dc47382047523 < 509d6a4d889e425f305461d8323a7b39ca6c121c
Linux >= 2ede0daf01549cecf4bb0962c46dc47382047523 < 4cb41f07685f88ec724a375883bb0c731db8f6eb
Linux >= 2ede0daf01549cecf4bb0962c46dc47382047523 < eeddee090b834a7d4b6a8214d2e3739e64c7a338
Linux >= 2ede0daf01549cecf4bb0962c46dc47382047523 < 8f75c19892263bc0555fba922aefe103e841e86d
Linux >= 2ede0daf01549cecf4bb0962c46dc47382047523 < 3dc22abc21f5892406c09202fa2627196cc96967
Linux 2.6.37

Full technical detail▾

Overview

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

btrfs: tree-checker: validate INODE_REF's namelen

[BUG] A crafted btrfs image can trigger the following crash:

BUG: unable to handle page fault for address: ffffd1dc42884000 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page CPU: 9 UID: 0 PID: 1034 Comm: poc Not tainted 7.1.0-rc4-custom+ #383 PREEMPT(full) 46af0a92938a63be7132e0dfd71e62327c51d5c2 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS unknown 02/02/2022 RIP: 0010:memcpy+0xc/0x10 Call Trace: <TASK> read_extent_buffer+0xe4/0x100 [btrfs 3cf0785dd58fec8c5ff84633b772f17ce1f92a8f] btrfs_get_name+0x15e/0x1e0 [btrfs 3cf0785dd58fec8c5ff84633b772f17ce1f92a8f] reconnect_path+0x165/0x390 exportfs_decode_fh_raw+0x337/0x400 ? drop_caches_sysctl_handler+0xb0/0xb0 </TASK> ---[ end trace 0000000000000000 ]--- RIP: 0010:memcpy+0xc/0x10 Kernel panic - not syncing: Fatal exception

[CAUSE] TThe crafted image has the following corrupted INODE_REF item:

     item 9 key (258 INODE_REF 257) itemoff 11544 itemsize 4106
     	index 2 namelen 4096 name: d\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000

The itemsize matches the namelen, but the namelen is 4096, way larger than normal name length limit (BTRFS_NAME_LEN, 255).

Meanwhile the memory of the @name is only 255 byte sized, this will cause out-of-boundary access, and cause the above crash.

[FIX] Add extra namelen verification for INODE_REF, just like what we have done in ROOT_REF checks.

Now the crafted image can be rejected gracefully:

BTRFS critical (device dm-2): corrupt leaf: root=5 block=30572544 slot=14 ino=259, invalid inode ref name length, has 4096 expect [1, 255] BTRFS error (device dm-2): read time tree block corruption detected on logical 30572544 mirror 2

[ Rebase, add a Link: tag, add an simple cause analyze ]

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

References

Change history

Field changes observed since this record was first indexed.

Sep 25, 2026CVSS — → 7.8
Sep 25, 2026Severity none → high

Related vulnerabilities

Connected by shared product, vendor, weakness, or advisory.

#nvd#cve.org

▾ Twilight zone — High severity, or a signal on a lesser flaw

Depth score43/ 100 · Moderate

impact 42.9 · likelihood 0 · exploitation 0

Overview

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

btrfs: tree-checker: validate INODE_REF's namelen

[BUG] A crafted btrfs image can trigger the following crash:

[CAUSE] TThe crafted image has the following corrupted INODE_REF item:

item 9 key (258 INODE_REF 257) itemoff 11544 itemsize 4106 index 2 namelen 4096 name: d\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000

The itemsize matches the namelen, but the namelen is 4096, way larger than normal name length limit (BTRFS_NAME_LEN, 255).

Meanwhile the memory of the @name is only 255 byte sized, this will cause out-of-boundary access, and cause the above crash.

[FIX] Add extra namelen verification for INODE_REF, just like what we have done in ROOT_REF checks.

Now the crafted image can be rejected gracefully:

[ Rebase, add a Link: tag, add an simple cause analyze ]