CVEvulnerability
CVE-2026-93207
9.8 CRITICAL
Official page ↗
- Status
- Received
- Published
- 2026-09-24
- Last modified
- 2026-10-19
- Assigner
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
- CVSS 3.1 (416baaa9-dc9f-4396-8d5f-8c081fb06d67)
- 9.8 CRITICAL — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Description
In the Linux kernel, the following vulnerability has been resolved:
SUNRPC: Zero rpc_gss_wire_cred at svcauth_gss_decode_credbody() entry
svcauth_gss_decode_credbody() writes the caller's
rpc_gss_wire_cred field by field and assigns gc_ctx.len only on
the success tail. The caller storage is svcdata->clcred, which
lives in the per-svc_rqst gss_svc_data and is reused across
requests. Early decode failures leave partially decoded state
mixed with residue from the prior request.
The trailing body_len tightness check is the sharpest case:
xdr_stream_decode_opaque_inline() has already written gc_ctx.data
with a borrowed inline pointer into the current request's XDR
pages, but gc_ctx.len retains its prior value. Once the request
pages are released the pooled clcred carries a dangling pointer
paired with a stale length.
Zero the caller's rpc_gss_wire_cred at function entry so that
every early-return path leaves a deterministic all-zero cred.
On the trailing tightness-check path, gc_ctx.len is now zero
instead of stale, which neuters length-driven consumers such as
gss_svc_searchbyctx() that would otherwise walk the dangling
data pointer.
References
- https://git.kernel.org/stable/c/0e18641708eaa8bc3c1ff338cd844aeadbd52bac git.kernel.org
- https://git.kernel.org/stable/c/0fa8a8acae57e6373962741d5b06d13f44aba6a9 git.kernel.org
- https://git.kernel.org/stable/c/11539e8fcce0b0af062ae5fecf7b3676c2f7aeed git.kernel.org
- https://git.kernel.org/stable/c/56b29d62017c7dd1718d060dd5b3a2ce61095d0c git.kernel.org
- https://git.kernel.org/stable/c/e0778464049b0238f2915a40007a4154f86cf351 git.kernel.org