In the Linux kernel, the following vulnerability has been resolved: ext4: fix off-by-one error in do_split Syzkaller detected a use-after-free issue in ext4_insert_dentry that was caused by out-of-bounds access due to incorrect splitting in do_split. BUG: KASAN: use-after-free in ext4_insert_dentry+0x36a/0x6d0 fs/ext4/namei.c:2109 Write of size 251 at addr ffff888074572f14 by task syz-executor335/5847 CPU: 0 UID: 0 PID: 5847 Comm: syz-executor335 Not tainted 6.12.0-rc6-syzkaller-00318-ga9cda7c0ffed #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024 Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:377 [inline] print_report+0x169/0x550 mm/kasan/report.c:488 kasan_report+0x143/0x180 mm/kasan/report.c:601 kasan_check_range+0x282/0x290 mm/kasan/generic.c:189 __asan_memcpy+0x40/0x70 mm/kasan/shadow.c:106 ext4_insert_dentry+0x36a/0x6d0 fs/ext4/namei.c:2109 add_dirent_to_buf+0x3d9/0x750 fs/ext4/namei.c:2154 make_indexed_dir+0xf98/0x1600 fs/ext4/namei.c:2351 ext4_add_entry+0x222a/0x25d0 fs/ext4/namei.c:2455 ext4_add_nondir+0x8d/0x290 fs/ext4/namei.c:2796 ext4_symlink+0x920/0xb50 fs/ext4/namei.c:3431 vfs_symlink+0x137/0x2e0 fs/namei.c:4615 do_symlinkat+0x222/0x3a0 fs/namei.c:4641 __do_sys_symlink fs/namei.c:4662 [inline] __se_sys_symlink fs/namei.c:4660 [inline] __x64_sys_symlink+0x7a/0x90 fs/namei.c:4660 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f </TASK> The following loop is located right above 'if' statement. for (i = count-1; i >= 0; i--) { /* is more than half of this entry in 2nd half of the block? */ if (size + map[i].size/2 > blocksize/2) break; size += map[i].size; move++; } 'i' in this case could go down to -1, in which case sum of active entries wouldn't exceed half the block size, but previous behaviour would also do split in half if sum would exceed at the very last block, which in case of having too many long name files in a single block could lead to out-of-bounds access and following use-after-free. Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
This vulnerability carries a MEDIUM severity rating with a CVSS v3.1 score of 5.5, requiring local system access to exploit with relatively low complexity without requiring user interaction requiring only low-level privileges . The vulnerability impacts and availability (service disruption) for affected systems. Impacting 2 products from linux, from debian organizations running these solutions should prioritize assessment and patching.
Reported in 2025, this vulnerability emerged during an era marked by increased sophistication in supply chain attacks, cloud infrastructure vulnerabilities, and software-as-a-service (SaaS) security challenges. Security practices during this period emphasized zero-trust architectures, container security, and API protection.
2025-05-01T13:15:50.893
2025-11-05T18:03:36.057
Analyzed
416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSSv3.1: 5.5 (MEDIUM)
| Type | Vendor | Product | Version/Range | Vulnerable? |
|---|---|---|---|---|
| Operating System | linux | linux_kernel | < 4.5 | Yes |
| Operating System | linux | linux_kernel | < 4.10 | Yes |
| Operating System | linux | linux_kernel | < 4.15 | Yes |
| Operating System | linux | linux_kernel | < 4.20 | Yes |
| Operating System | linux | linux_kernel | < 5.4.293 | Yes |
| Operating System | linux | linux_kernel | < 5.8 | Yes |
| Operating System | linux | linux_kernel | < 5.9 | Yes |
| Operating System | linux | linux_kernel | < 5.10.237 | Yes |
| Operating System | linux | linux_kernel | < 5.15.181 | Yes |
| Operating System | linux | linux_kernel | < 6.1.135 | Yes |
| Operating System | linux | linux_kernel | < 6.6.88 | Yes |
| Operating System | linux | linux_kernel | < 6.12.24 | Yes |
| Operating System | linux | linux_kernel | < 6.13.12 | Yes |
| Operating System | linux | linux_kernel | < 6.14.3 | Yes |
| Operating System | linux | linux_kernel | 5.9 | Yes |
| Operating System | linux | linux_kernel | 5.9 | Yes |
| Operating System | linux | linux_kernel | 5.9 | Yes |
| Operating System | linux | linux_kernel | 5.9 | Yes |
| Operating System | linux | linux_kernel | 5.9 | Yes |
| Operating System | linux | linux_kernel | 5.9 | Yes |
| Operating System | linux | linux_kernel | 5.9 | Yes |
| Operating System | linux | linux_kernel | 5.9 | Yes |
| Operating System | linux | linux_kernel | 6.15 | Yes |
| Operating System | debian | debian_linux | 11.0 | Yes |
SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For linux's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.