{"cve":"CVE-2025-38034","nvd":{"published":"2025-06-18T10:15:35.593","modified":"2026-06-17T09:15:55.243","status":"Analyzed","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: correct the order of prelim_ref arguments in btrfs__prelim_ref\n\nbtrfs_prelim_ref() calls the old and new reference variables in the\nincorrect order. This causes a NULL pointer dereference because oldref\nis passed as NULL to trace_btrfs_prelim_ref_insert().\n\nNote, trace_btrfs_prelim_ref_insert() is being called with newref as\noldref (and oldref as NULL) on purpose in order to print out\nthe values of newref.\n\nTo reproduce:\necho 1 > /sys/kernel/debug/tracing/events/btrfs/btrfs_prelim_ref_insert/enable\n\nPerform some writeback operations.\n\nBacktrace:\nBUG: kernel NULL pointer dereference, address: 0000000000000018\n #PF: supervisor read access in kernel mode\n #PF: error_code(0x0000) - not-present page\n PGD 115949067 P4D 115949067 PUD 11594a067 PMD 0\n Oops: Oops: 0000 [#1] SMP NOPTI\n CPU: 1 UID: 0 PID: 1188 Comm: fsstress Not tainted 6.15.0-rc2-tester+ #47 PREEMPT(voluntary)  7ca2cef72d5e9c600f0c7718adb6462de8149622\n Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-2-gc13ff2cd-prebuilt.qemu.org 04/01/2014\n RIP: 0010:trace_event_raw_event_btrfs__prelim_ref+0x72/0x130\n 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\n RSP: 0018:ffffce44820077a0 EFLAGS: 00010286\n RAX: ffff8c6b403f9014 RBX: ffff8c6b55825730 RCX: 304994edf9cf506b\n RDX: d8b11eb7f0fdb699 RSI: ffff8c6b403f9010 RDI: ffff8c6b403f9010\n RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000010\n R10: 00000000ffffffff R11: 0000000000000000 R12: ffff8c6b4e8fb000\n R13: 0000000000000000 R14: ffffce44820077a8 R15: ffff8c6b4abd1540\n FS:  00007f4dc6813740(0000) GS:ffff8c6c1d378000(0000) knlGS:0000000000000000\n CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n CR2: 0000000000000018 CR3: 000000010eb42000 CR4: 0000000000750ef0\n PKRU: 55555554\n Call Trace:\n  <TASK>\n  prelim_ref_insert+0x1c1/0x270\n  find_parent_nodes+0x12a6/0x1ee0\n  ? __entry_text_end+0x101f06/0x101f09\n  ? srso_alias_return_thunk+0x5/0xfbef5\n  ? srso_alias_return_thunk+0x5/0xfbef5\n  ? srso_alias_return_thunk+0x5/0xfbef5\n  ? srso_alias_return_thunk+0x5/0xfbef5\n  btrfs_is_data_extent_shared+0x167/0x640\n  ? fiemap_process_hole+0xd0/0x2c0\n  extent_fiemap+0xa5c/0xbc0\n  ? __entry_text_end+0x101f05/0x101f09\n  btrfs_fiemap+0x7e/0xd0\n  do_vfs_ioctl+0x425/0x9d0\n  __x64_sys_ioctl+0x75/0xc0","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":5.5},"cwes":["CWE-476"],"references":["https://git.kernel.org/stable/c/0528bba48dce7820d2da72e1a114e1c4552367eb","https://git.kernel.org/stable/c/137bfa08c6441f324d00692d1e9d22cfd773329b","https://git.kernel.org/stable/c/5755b6731655e248c4f1d52a2e1b18795b4a2a3a","https://git.kernel.org/stable/c/7a97f961a568a8f72472dc804af02a0f73152c5f","https://git.kernel.org/stable/c/7f7c8c03feba5f2454792fab3bb8bd45bd6883f9"],"products":["debian:debian_linux","linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T22:03:23.287444849+00:00"},"epss":{"cve":"CVE-2025-38034","score":0.00213,"percentile":0.11653,"date":"2026-11-01"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}