In the Linux kernel, the following vulnerability has been resolved:
hfs: Fix OOB Write in hfs_asc2mac
Syzbot reported a OOB Write bug:
loop0: detected capacity change from 0 to 64 ================================================================== BUG: KASAN: slab-out-of-bounds in hfs_asc2mac+0x467/0x9a0 fs/hfs/trans.c:133 Write of size 1 at addr ffff88801848314e by task syz-executor391/3632
Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1b1/0x28e lib/dump_stack.c:106 print_address_description+0x74/0x340 mm/kasan/report.c:284 print_report+0x107/0x1f0 mm/kasan/report.c:395 kasan_report+0xcd/0x100 mm/kasan/report.c:495 hfs_asc2mac+0x467/0x9a0 fs/hfs/trans.c:133 hfs_cat_build_key+0x92/0x170 fs/hfs/catalog.c:28 hfs_lookup+0x1ab/0x2c0 fs/hfs/dir.c:31 lookup_open fs/namei.c:3391 [inline] open_last_lookups fs/namei.c:3481 [inline] path_openat+0x10e6/0x2df0 fs/namei.c:3710 do_filp_open+0x264/0x4f0 fs/namei.c:3740
If in->len is much larger than HFS_NAMELEN(31) which is the maximum length of an HFS filename, a OOB write could occur in hfs_asc2mac(). In that case, when the dst reaches the boundary, the srclen is still greater than 0, which causes a OOB write. Fix this by adding a check on dstlen in while() before writing to dst address.
CVSS Details
- CVSS 3.1 Base Score: 7.8
- CVSS 3.1 Vector: (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Amazon Linux Ami 2 | — | Upgrade kernel-tools-develUpgrade perf-debuginfoUpgrade kernelUpgrade kernel-debuginfo-common-aarch64Upgrade kernel-debuginfoUpgrade kernel-develUpgrade kernel-livepatch-5.10.165-143.735Upgrade kernel-headersUpgrade perfUpgrade kernel-toolsUpgrade python-perfUpgrade kernel-tools-debuginfoUpgrade bpftoolUpgrade kernel-livepatch-4.14.304-226.531Upgrade python-perf-debuginfoUpgrade bpftool-debuginfoUpgrade kernel-debuginfo-common-x86_64 | May 20, 2026 | May 20, 2026 |
| Debian | — | Upgrade linux | Dec 29, 2025 | Dec 29, 2025 |
| Ubuntu | — | Upgrade linux-hwe-5.15Upgrade linux-raspiUpgrade linux-aws-fipsUpgrade linux-gcp-fipsUpgrade linux-realtimeUpgrade linux-iotUpgrade linux-gcp-4.15Upgrade linux-ibm-5.4Upgrade linux-azure-4.15Upgrade linuxUpgrade linux-hwe-5.4Upgrade linux-intel-iotg-5.15Upgrade linux-azure-5.4Upgrade linux-awsUpgrade linux-lowlatency-hwe-5.15Upgrade linux-azureUpgrade linux-ibmUpgrade linux-azure-fipsUpgrade linux-hweUpgrade linux-kvmUpgrade linux-nvidiaUpgrade linux-xilinx-zynqmpUpgrade linux-fipsUpgrade linux-intel-iot-realtimeUpgrade linux-bluefieldUpgrade linux-aws-hweUpgrade linux-oracleUpgrade linux-raspi-5.4Upgrade linux-gkeopUpgrade linux-riscv-5.15Upgrade linux-intel-iotgUpgrade linux-azure-5.15Upgrade linux-nvidia-tegra-5.15Upgrade linux-gcp-5.4Upgrade linux-oracle-5.4Upgrade linux-gkeUpgrade linux-gcpUpgrade linux-oracle-5.15Upgrade linux-gcp-5.15Upgrade linux-lowlatencyUpgrade linux-aws-5.4Upgrade linux-aws-5.15 | Jan 6, 2026 | Dec 24, 2025 |
| Vmware Photon_os | — | Use 'tdnf update' to upgrade all packages to the latest version. | May 27, 2026 | Dec 24, 2025 |
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