[CVE-2026-93207] In the Linux kernel, the following vulnerability has been resolved: SUNRPC: Zero rpc_gss_wire_cred …

Descripción técnica

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.

Puntuación CVSS

Score: 9.8/10 — Severidad: CRITICAL — Estado NIST: Received

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Fuente oficial

Publicado en NIST NVD.