CVE-2026-90042
In the Linux kernel, the following vulnerability has been resolved: ceph: properly decrypt filenames in vmalloc() buffers The fscrypt subsystem uses the scatterlist crypto API, inheriting its requirement that any buffers are in the linear mapping region.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.49%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
In the Linux kernel, the following vulnerability has been resolved: ceph: properly decrypt filenames in vmalloc() buffers The fscrypt subsystem uses the scatterlist crypto API, inheriting its requirement that any buffers are in the linear mapping region. However, the messenger client uses kvmalloc() to create buffers for messages, which will occasionally place those buffers in the vmalloc() region when physical memory fragmentation doesn't permit a large enough kmalloc(). The various callers of ceph_fname_to_usr() directly pass (slices of) raw messages from the MDS without considering that the messages may be in vmalloc() buffers, resulting in oopses especially on non-x86 platforms (see 'Closes:' for more details and a reproducer). Make ceph_fname_to_usr() explicitly tolerant of vmalloc()-allocated fname->ctext, fname->name, and/or oname->name buffers, using `tname` (which, when non-null, must be a linear address; when null, is briefly allocated as necessary) as a bounce buffer to avoid passing any inappropriate addresses to fscrypt_fname_disk_to_usr(). Additionally change parse_reply_info_readdir() -- the only function to supply its own `tname` -- to follow the new "tname must never come from vmalloc()" rule by passing NULL when the message is not in the linear region. Though this causes a per-dentry kmalloc()+kfree(), this overhead exists only when processing the minority of messages that spill into vmalloc(). My (crude) testing puts this at only about 1 in 8,000 readdir messages. Still, if the overhead proves unreasonable in the future, it is easy enough to mitigate: a future change could allocate a bounce buffer in parse_reply_info_readdir() and use that as `tname` instead.
- CVSS 3.1
- 9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.49% probability · 41th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
EPSS 0.5% since 19 September 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.