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CVE-2026-93207NVD
Vulnerability Summary
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.
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 v3.1 Base Metrics — Score 9.8 (CRITICAL)
Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
Affected & Patched Versions
Not provided by NVD for this CVE.
Not provided by NVD for this CVE.
External References
- https://git.kernel.org/stable/c/0e18641708eaa8bc3c1ff338cd844aeadbd52bac
- https://git.kernel.org/stable/c/0fa8a8acae57e6373962741d5b06d13f44aba6a9
- https://git.kernel.org/stable/c/11539e8fcce0b0af062ae5fecf7b3676c2f7aeed
- https://git.kernel.org/stable/c/56b29d62017c7dd1718d060dd5b3a2ce61095d0c
- https://git.kernel.org/stable/c/e0778464049b0238f2915a40007a4154f86cf351