CVE-2025-40349 Vulnerability Analysis & Exploit Details

CVE-2025-40349
Vulnerability Scoring

Analysis In Progress
Analysis In Progress

Attack Complexity Details

  • Attack Complexity:
    Attack Complexity Analysis In Progress
  • Attack Vector:
    Attack Vector Under Analysis
  • Privileges Required: None
    No authentication is required for exploitation.
  • Scope:
    Impact is confined to the initially vulnerable component.
  • User Interaction: None
    No user interaction is necessary for exploitation.

CVE-2025-40349 Details

Status: Awaiting Analysis

Last updated: 🕒 18 Dec 2025, 15:08 UTC
Originally published on: 🕑 16 Dec 2025, 14:15 UTC

Time between publication and last update: 2 days

CVSS Release:

CVE-2025-40349 Vulnerability Summary

CVE-2025-40349: In the Linux kernel, the following vulnerability has been resolved: hfs: validate record offset in hfsplus_bmap_alloc hfsplus_bmap_alloc can trigger a crash if a record offset or length is larger than node_size [ 15.264282] BUG: KASAN: slab-out-of-bounds in hfsplus_bmap_alloc+0x887/0x8b0 [ 15.265192] Read of size 8 at addr ffff8881085ca188 by task test/183 [ 15.265949] [ 15.266163] CPU: 0 UID: 0 PID: 183 Comm: test Not tainted 6.17.0-rc2-gc17b750b3ad9 #14 PREEMPT(voluntary) [ 15.266165] Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 15.266167] Call Trace: [ 15.266168] <TASK> [ 15.266169] dump_stack_lvl+0x53/0x70 [ 15.266173] print_report+0xd0/0x660 [ 15.266181] kasan_report+0xce/0x100 [ 15.266185] hfsplus_bmap_alloc+0x887/0x8b0 [ 15.266208] hfs_btree_inc_height.isra.0+0xd5/0x7c0 [ 15.266217] hfsplus_brec_insert+0x870/0xb00 [ 15.266222] __hfsplus_ext_write_extent+0x428/0x570 [ 15.266225] __hfsplus_ext_cache_extent+0x5e/0x910 [ 15.266227] hfsplus_ext_read_extent+0x1b2/0x200 [ 15.266233] hfsplus_file_extend+0x5a7/0x1000 [ 15.266237] hfsplus_get_block+0x12b/0x8c0 [ 15.266238] __block_write_begin_int+0x36b/0x12c0 [ 15.266251] block_write_begin+0x77/0x110 [ 15.266252] cont_write_begin+0x428/0x720 [ 15.266259] hfsplus_write_begin+0x51/0x100 [ 15.266262] cont_write_begin+0x272/0x720 [ 15.266270] hfsplus_write_begin+0x51/0x100 [ 15.266274] generic_perform_write+0x321/0x750 [ 15.266285] generic_file_write_iter+0xc3/0x310 [ 15.266289] __kernel_write_iter+0x2fd/0x800 [ 15.266296] dump_user_range+0x2ea/0x910 [ 15.266301] elf_core_dump+0x2a94/0x2ed0 [ 15.266320] vfs_coredump+0x1d85/0x45e0 [ 15.266349] get_signal+0x12e3/0x1990 [ 15.266357] arch_do_signal_or_restart+0x89/0x580 [ 15.266362] irqentry_exit_to_user_mode+0xab/0x110 [ 15.266364] asm_exc_page_fault+0x26/0x30 [ 15.266366] RIP: 0033:0x41bd35 [ 15.266367] Code: bc d1 f3 0f 7f 27 f3 0f 7f 6f 10 f3 0f 7f 77 20 f3 0f 7f 7f 30 49 83 c0 0f 49 29 d0 48 8d 7c 17 31 e9 9f 0b 00 00 66 0f ef c0 <f3> 0f 6f 0e f3 0f 6f 56 10 66 0f 74 c1 66 0f d7 d0 49 83 f8f [ 15.266369] RSP: 002b:00007ffc9e62d078 EFLAGS: 00010283 [ 15.266371] RAX: 00007ffc9e62d100 RBX: 0000000000000000 RCX: 0000000000000000 [ 15.266372] RDX: 00000000000000e0 RSI: 0000000000000000 RDI: 00007ffc9e62d100 [ 15.266373] RBP: 0000400000000040 R08: 00000000000000e0 R09: 0000000000000000 [ 15.266374] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 [ 15.266375] R13: 0000000000000000 R14: 0000000000000000 R15: 0000400000000000 [ 15.266376] </TASK> When calling hfsplus_bmap_alloc to allocate a free node, this function first retrieves the bitmap from header node and map node using node->page together with the offset and length from hfs_brec_lenoff ``` len = hfs_brec_lenoff(node, 2, &off16); off = off16; off += node->page_offset; pagep = node->page + (off >> PAGE_SHIFT); data = kmap_local_page(*pagep); ``` However, if the retrieved offset or length is invalid(i.e. exceeds node_size), the code may end up accessing pages outside the allocated range for this node. This patch adds proper validation of both offset and length before use, preventing out-of-bounds page access. Move is_bnode_offset_valid and check_and_correct_requested_length to hfsplus_fs.h, as they may be required by other functions.

Assessing the Risk of CVE-2025-40349

Access Complexity Graph

The exploitability of CVE-2025-40349 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).

Exploitability Analysis for CVE-2025-40349

No exploitability data is available for CVE-2025-40349.

Understanding AC and PR

A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.

Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.

Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.

CVSS Score Breakdown Chart

Above is the CVSS Sub-score Breakdown for CVE-2025-40349, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.

CIA Impact Analysis

Below is the Impact Analysis for CVE-2025-40349, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.

  • Confidentiality: None
    CVE-2025-40349 does not compromise confidentiality.
  • Integrity: None
    CVE-2025-40349 does not impact data integrity.
  • Availability: None
    CVE-2025-40349 does not affect system availability.

CVE-2025-40349 References

External References

CWE Common Weakness Enumeration

Unknown

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