PT-2026-90390 · Linux · Linux
CVE-2026-89674
·
Publicado
2026-09-11
·
Atualizado
2026-09-11
CVSS v3.1
9.8
Crítica
| Vetor | AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
In the Linux kernel, the following vulnerability has been resolved:
nfsd: fix XDR length calculation in nfsd4 ff encode layoutget
The XDR buffer size calculation in nfsd4 ff encode layoutget() has
multiple errors that can result in either an out-of-bounds write or
leaking uninitialized kernel memory to the client:
- fh len doesn't account for XDR padding on the file handle data
- uid and gid lengths use "8 + len" but xdr encode opaque() actually writes "4 + xdr align size(len)" bytes
- ds len omits the flags and stats collect hint fields (8 bytes), while len's header constant overestimates by 8 bytes -- these partially cancel but leave a net mismatch
The worst case occurs with short strings (e.g. uid=0, gid=0 with an
odd-sized file handle), where the function writes up to 5 bytes past
the reserved XDR buffer. Conversely, when string lengths happen to be
4-byte aligned, the reservation is too large and stale buffer content
is sent to the client.
Fix this by breaking out every encoded field explicitly in the ds len
calculation, using xdr align size() for all variable-length opaque
fields, and correcting the header constants.
Correção
Encontrou algum problema na descrição? Tem algo a acrescentar? Fique à vontade para nos escrever 👾
Identificadores relacionados
Produtos afetados
Linux