Paper/Archive/CVE-2026-93207

CVE-2026-93207

Linux Linux — SUNRPC: Zero rpc_gss_wire_cred at svcauth_gss_decode_credbody() entry

Description · from the CVE record

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.

Affected

ProductAffectedFixed inSource
Linuxb0bc53470d1af01f62a0fe2d405cf56477804863 – < 56b29d62017c7dd1718d060dd5b3a2ce61095d0c56b29d62017c7dd1718d060dd5b3a2ce61095d0cCNA
Linuxb0bc53470d1af01f62a0fe2d405cf56477804863 – < 0e18641708eaa8bc3c1ff338cd844aeadbd52bac0e18641708eaa8bc3c1ff338cd844aeadbd52bacCNA
Linuxb0bc53470d1af01f62a0fe2d405cf56477804863 – < e0778464049b0238f2915a40007a4154f86cf351e0778464049b0238f2915a40007a4154f86cf351CNA
Linuxb0bc53470d1af01f62a0fe2d405cf56477804863 – < 0fa8a8acae57e6373962741d5b06d13f44aba6a90fa8a8acae57e6373962741d5b06d13f44aba6a9CNA
Linuxb0bc53470d1af01f62a0fe2d405cf56477804863 – < 11539e8fcce0b0af062ae5fecf7b3676c2f7aeed11539e8fcce0b0af062ae5fecf7b3676c2f7aeedCNA
Linux6.36.6.157CNA

Scores by source

Linux (CNA)9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References

refgit.kernel.org/stable/c/56b29d62017c7dd1718d060dd5b3a2ce61095d0crefgit.kernel.org/stable/c/0e18641708eaa8bc3c1ff338cd844aeadbd52bacrefgit.kernel.org/stable/c/e0778464049b0238f2915a40007a4154f86cf351refgit.kernel.org/stable/c/0fa8a8acae57e6373962741d5b06d13f44aba6a9refgit.kernel.org/stable/c/11539e8fcce0b0af062ae5fecf7b3676c2f7aeed