CVE-2025-38034: debian debian_linux NULL Pointer Dereference
Vulnerability summary
CVE-2025-38034 is a medium (CVSS 5.5) NULL Pointer Dereference vulnerability in debian debian_linux. EPSS estimates a 0.21% chance of exploitation in the next 30 days, higher than 10.3% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 51 · Related 48Timeline
- 18-06-2025PublishedVulnerability first disclosed.
- 11-05-2026Last modifiedVulnerability information updated.
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
CVSS metrics
3 scores · 3 sources · 1 version- OSV · UbuntuEcosystem advisory · calculated5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- OSV · DebianEcosystem advisory · calculated5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
0.21%
Chance of exploitation in the next 30 days
Percentile
10%
Versus all other CVEs
30-day change
0.00 pp
From 0.21% on 19-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Ubuntu146 products
- linuxAll versions (No fix recorded) | < 5.15.0-152.162 | < 6.8.0-100.100
- linux-allwinner-5.19All versions (No fix recorded)
- linux-awsAll versions (No fix recorded) | < 5.15.0-1090.97 | < 6.8.0-1046.49
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11All versions (No fix recorded)
Debian2 products
- linux< 6.1.147-1 | < 6.12.32-1
- debian_linuxEOL11.0
Linux2 products
- linux≥ 00142756e1f8015d2f8ce96532d156689db7e448, < 5755b6731655e248c4f1d52a2e1b18795b4a2a3a | ≥ 00142756e1f8015d2f8ce96532d156689db7e448, < a641154cedf9d69730f8af5d0a901fe86e6486bd | ≥ 00142756e1f8015d2f8ce96532d156689db7e448, < a876703894a6dd6e8c04b0635d86e9f7a7c81b79 | ≥ 00142756e1f8015d2f8ce96532d156689db7e448, < 0528bba48dce7820d2da72e1a114e1c4552367eb | ≥ 00142756e1f8015d2f8ce96532d156689db7e448, < 7a97f961a568a8f72472dc804af02a0f73152c5f | ≥ 00142756e1f8015d2f8ce96532d156689db7e448, < 7f7c8c03feba5f2454792fab3bb8bd45bd6883f9 | ≥ 00142756e1f8015d2f8ce96532d156689db7e448, < 137bfa08c6441f324d00692d1e9d22cfd773329b | ≥ 00142756e1f8015d2f8ce96532d156689db7e448, < bc7e0975093567f51be8e1bdf4aa5900a3cf0b1e | 4.14
- linux_kernel< 5.4.294 | ≥ 5.5, < 5.10.238 | ≥ 5.11, < 5.15.185 | ≥ 5.16, < 6.1.141 | ≥ 6.2, < 6.6.93 | ≥ 6.7, < 6.12.31 | ≥ 6.13, < 6.14.9 | 6.15:rc1 | 6.15:rc2 | 6.15:rc3 | 6.15:rc4 | 6.15:rc5
3 vendors · 150 products
References
46 links- lists.debian.org/debian-lts-announce/2025/10/msg00008.htmlThird Party Advisory
- lists.debian.org/debian-lts-announce/2025/10/msg00007.htmlThird Party Advisory