CVE-2025-38059None▾ Sunlit

btrfs: avoid NULL pointer dereference if no valid csum tree

In the Linux kernel, the following vulnerability has been resolved: btrfs: avoid NULL pointer dereference if no valid csum tree [BUG] When trying read-only scrub on a btrfs with rescue=idatacsums mount option, it will crash with the fo…

▾ Sunlit zone — Low / medium · no exploitation signal

Depth score3/ 100 · Minimal

impact 2.8 · likelihood 0 · exploitation 0

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Proof of concept

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Published

Jun 18, 2025

Updated

Oct 30, 2026

CVSS

—

Vendor

Linux

Product

Linux

CWE

—

Depth score

3 · Minimal

EPSS

0.19% · p9

Platforms

—

Source

CVEORG

Vector

—

EPSS history

Exploit-prediction probability, daily snapshots since Nov 3.

0.2% → 0.2%

Timeline

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

3 events · 503 days

Jun 18, 2025Published
Disclosed via CVEORG
Oct 30, 2026Record revised
Last analysed / modified upstream
Nov 3, 2026EPSS first tracked
0.2%

Linux #cve.org

Affected

Linux >= 74ef00185eb864252156022ff129b01549504175 < 2db25048a61c0909459b074af04e06ab8a8b939e
Linux >= 74ef00185eb864252156022ff129b01549504175 < 50d0de59f66cbe6d597481e099bf1c70fd07e0a9
Linux >= 74ef00185eb864252156022ff129b01549504175 < 6e9770de024964b1017f99ee94f71967bd6edaeb
Linux >= 74ef00185eb864252156022ff129b01549504175 < d35bed14b0bc95c6845863a3744ecd10b888c830
Linux >= 74ef00185eb864252156022ff129b01549504175 < f95d186255b319c48a365d47b69bd997fecb674e
Linux 5.9

Full technical detail▾

Overview

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

btrfs: avoid NULL pointer dereference if no valid csum tree

[BUG] When trying read-only scrub on a btrfs with rescue=idatacsums mount option, it will crash with the following call trace:

BUG: kernel NULL pointer dereference, address: 0000000000000208 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page CPU: 1 UID: 0 PID: 835 Comm: btrfs Tainted: G O 6.15.0-rc3-custom+ #236 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS unknown 02/02/2022 RIP: 0010:btrfs_lookup_csums_bitmap+0x49/0x480 [btrfs] Call Trace: <TASK> scrub_find_fill_first_stripe+0x35b/0x3d0 [btrfs] scrub_simple_mirror+0x175/0x290 [btrfs] scrub_stripe+0x5f7/0x6f0 [btrfs] scrub_chunk+0x9a/0x150 [btrfs] scrub_enumerate_chunks+0x333/0x660 [btrfs] btrfs_scrub_dev+0x23e/0x600 [btrfs] btrfs_ioctl+0x1dcf/0x2f80 [btrfs] __x64_sys_ioctl+0x97/0xc0 do_syscall_64+0x4f/0x120 entry_SYSCALL_64_after_hwframe+0x76/0x7e

[CAUSE] Mount option "rescue=idatacsums" will completely skip loading the csum tree, so that any data read will not find any data csum thus we will ignore data checksum verification.

Normally call sites utilizing csum tree will check the fs state flag NO_DATA_CSUMS bit, but unfortunately scrub does not check that bit at all.

This results in scrub to call btrfs_search_slot() on a NULL pointer and triggered above crash.

[FIX] Check both extent and csum tree root before doing any tree search.

Affected

Linux >= 74ef00185eb864252156022ff129b01549504175 < 2db25048a61c0909459b074af04e06ab8a8b939e
Linux >= 74ef00185eb864252156022ff129b01549504175 < 50d0de59f66cbe6d597481e099bf1c70fd07e0a9
Linux >= 74ef00185eb864252156022ff129b01549504175 < 6e9770de024964b1017f99ee94f71967bd6edaeb
Linux >= 74ef00185eb864252156022ff129b01549504175 < d35bed14b0bc95c6845863a3744ecd10b888c830
Linux >= 74ef00185eb864252156022ff129b01549504175 < f95d186255b319c48a365d47b69bd997fecb674e
Linux 5.9

Remediation

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

References

Related vulnerabilities

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

#cve.org

btrfs: avoid NULL pointer dereference if no valid csum tree

▾ Sunlit zone — Low / medium · no exploitation signal

Depth score3/ 100 · Minimal

impact 2.8 · likelihood 0 · exploitation 0

Overview

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

btrfs: avoid NULL pointer dereference if no valid csum tree

[BUG] When trying read-only scrub on a btrfs with rescue=idatacsums mount option, it will crash with the following call trace:

[CAUSE] Mount option "rescue=idatacsums" will completely skip loading the csum tree, so that any data read will not find any data csum thus we will ignore data checksum verification.

Normally call sites utilizing csum tree will check the fs state flag NO_DATA_CSUMS bit, but unfortunately scrub does not check that bit at all.

This results in scrub to call btrfs_search_slot() on a NULL pointer and triggered above crash.

[FIX] Check both extent and csum tree root before doing any tree search.

Affected

Linux >= 74ef00185eb864252156022ff129b01549504175 < 2db25048a61c0909459b074af04e06ab8a8b939e

Linux >= 74ef00185eb864252156022ff129b01549504175 < 50d0de59f66cbe6d597481e099bf1c70fd07e0a9

Linux >= 74ef00185eb864252156022ff129b01549504175 < 6e9770de024964b1017f99ee94f71967bd6edaeb

Linux >= 74ef00185eb864252156022ff129b01549504175 < d35bed14b0bc95c6845863a3744ecd10b888c830

Linux >= 74ef00185eb864252156022ff129b01549504175 < f95d186255b319c48a365d47b69bd997fecb674e

Linux 5.9