CVE-2026-93207
CRITICALDescription
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.
CVSS v3 vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Affected routers (0)
No routers currently mapped to this CVE in our database.