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DEBIAN-CVE-2025-38034

MediumCVSS 5.5 / 10
Published Jun 18, 2025·Last modified Jun 15, 2026
Affected Components(0)

No affected components available

Description

In the Linux kernel, the following vulnerability has been resolved: btrfs: correct the order of prelim_ref arguments in btrfs__prelim_ref btrfs_prelim_ref() calls the old and new reference variables in the incorrect order. This causes a NULL pointer dereference because oldref is passed as NULL to trace_btrfs_prelim_ref_insert(). Note, trace_btrfs_prelim_ref_insert() is being called with newref as oldref (and oldref as NULL) on purpose in order to print out the values of newref. To reproduce: echo 1 > /sys/kernel/debug/tracing/events/btrfs/btrfs_prelim_ref_insert/enable Perform some writeback operations. Backtrace: BUG: kernel NULL pointer dereference, address: 0000000000000018 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 115949067 P4D 115949067 PUD 11594a067 PMD 0 Oops: Oops: 0000 [#1] SMP NOPTI CPU: 1 UID: 0 PID: 1188 Comm: fsstress Not tainted 6.15.0-rc2-tester+ #47 PREEMPT(voluntary) 7ca2cef72d5e9c600f0c7718adb6462de8149622 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-2-gc13ff2cd-prebuilt.qemu.org 04/01/2014 RIP: 0010:trace_event_raw_event_btrfs__prelim_ref+0x72/0x130 Code: e8 43 81 9f ff 48 85 c0 74 78 4d 85 e4 0f 84 8f 00 00 00 49 8b 94 24 c0 06 00 00 48 8b 0a 48 89 48 08 48 8b 52 08 48 89 50 10 <49> 8b 55 18 48 89 50 18 49 8b 55 20 48 89 50 20 41 0f b6 55 28 88 RSP: 0018:ffffce44820077a0 EFLAGS: 00010286 RAX: ffff8c6b403f9014 RBX: ffff8c6b55825730 RCX: 304994edf9cf506b RDX: d8b11eb7f0fdb699 RSI: ffff8c6b403f9010 RDI: ffff8c6b403f9010 RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000010 R10: 00000000ffffffff R11: 0000000000000000 R12: ffff8c6b4e8fb000 R13: 0000000000000000 R14: ffffce44820077a8 R15: ffff8c6b4abd1540 FS: 00007f4dc6813740(0000) GS:ffff8c6c1d378000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000018 CR3: 000000010eb42000 CR4: 0000000000750ef0 PKRU: 55555554 Call Trace: <TASK> prelim_ref_insert+0x1c1/0x270 find_parent_nodes+0x12a6/0x1ee0 ? __entry_text_end+0x101f06/0x101f09 ? srso_alias_return_thunk+0x5/0xfbef5 ? srso_alias_return_thunk+0x5/0xfbef5 ? srso_alias_return_thunk+0x5/0xfbef5 ? srso_alias_return_thunk+0x5/0xfbef5 btrfs_is_data_extent_shared+0x167/0x640 ? fiemap_process_hole+0xd0/0x2c0 extent_fiemap+0xa5c/0xbc0 ? __entry_text_end+0x101f05/0x101f09 btrfs_fiemap+0x7e/0xd0 do_vfs_ioctl+0x425/0x9d0 __x64_sys_ioctl+0x75/0xc0

Risk Scores
Base Score
5.5

The vulnerability requires local access to the device to be exploited. It is easy for an attacker to exploit this vulnerability. An attacker needs basic access or low-level privileges. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a high impact on the availability of the system.

Threat Intelligence
5.1

Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.

EPSS
N/A

Probability that this vulnerability will be exploited in the wild within the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

Related Vulnerabilities
  • CVE-2025-38034
    Upstream
  • EUVD-2025-18618
    Upstream

Browse More

Medium severity
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