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CVE Record

CVE-2022-50747: hfs: Fix OOB Write in hfs_asc2mac

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.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This is a Linux kernel bug in HFS filesystem handling. A specially malformed HFS filename can cause an out-of-bounds kernel memory write. Business risk is mainly where systems mount or process untrusted HFS disk images or media. No source indicates active exploitation.

Executive priority

Treat as a patch-cycle priority, not an emergency, unless your environment processes untrusted HFS media. Kernel memory corruption can be serious, but current sources show no active exploitation and limited triggering context.

Technical view

The flaw is in hfs_asc2mac() in fs/hfs/trans.c. If input length exceeds the HFS filename maximum of 31, the destination buffer boundary can be reached while source bytes remain, causing a slab out-of-bounds write. The kernel fix adds a destination-length check before writing.

Likely exposure

Linux systems with affected kernels and HFS filesystem support are relevant. Exposure is highest on endpoints, forensic systems, file-processing services, or removable-media workflows that may mount HFS images. Distribution-specific status depends on backports.

Exploitation context

The public description comes from syzbot/KASAN testing and kernel stable fixes. The sources do not show active exploitation, public weaponization, or remote network exploitation. Practical triggering appears tied to handling a crafted HFS filesystem object.

Researcher notes

The CVE record lists severity as unknown and provides kernel stable commit references. The affected-version data in the bundle is not distribution-specific. Validate against upstream commits and downstream vendor changelogs rather than relying only on kernel version strings.

Mitigation direction

  • Update to a vendor kernel containing the referenced HFS fix or downstream equivalent.
  • Prioritize systems that mount removable media or untrusted filesystem images.
  • If HFS is unnecessary, review vendor-supported options to restrict HFS mounting.
  • Track Linux distribution advisories for backported fixes and package names.

Validation and detection

  • Inventory Linux kernel versions across affected systems.
  • Confirm whether the kernel includes a referenced stable commit or vendor backport.
  • Identify systems with HFS filesystem support enabled or in use.
  • Review logs and workflows for mounting untrusted HFS images or media.
Prepared
Confidence
medium
Sources
11

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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CVE-2022-50747 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
0Timeline events
0ADP providers
10Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux328b9227865026268261a24a97a578907b280415, 328b9227865026268261a24a97a578907b280415, 328b9227865026268261a24a97a578907b280415, 328b9227865026268261a24a97a578907b280415, 328b9227865026268261a24a97a578907b280415, 328b9227865026268261a24a97a578907b280415, 328b9227865026268261a24a97a578907b280415, 328b9227865026268261a24a97a578907b280415, 328b9227865026268261a24a97a578907b280415unaffected
LinuxLinux2.6.14, 0, 4.9.337, 4.14.303, 4.19.270, 5.4.229, 5.10.163, 5.15.86, 6.0.16, 6.1.2, 6.2affected
Weakness

CWE details

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