In the Linux kernel, the following vulnerability has been resolved:
nfsd: fix XDR length calculation in nfsd4_ff_encode_layoutget
The XDR buffer size calculation in nfsd4_ff_encode_layoutget() has
multiple errors that can result in either an out-of-bounds write or
leaking uninitialized kernel memory to the client:
- fh_len doesn't account for XDR padding on the file handle data
- uid and gid lengths use "8 + len" but xdr_encode_opaque() actually
writes "4 + xdr_align_size(len)" bytes
- ds_len omits the flags and stats_collect_hint fields (8 bytes),
while len's header constant overestimates by 8 bytes -- these
partially cancel but leave a net mismatch
The worst case occurs with short strings (e.g. uid=0, gid=0 with an
odd-sized file handle), where the function writes up to 5 bytes past
the reserved XDR buffer. Conversely, when string lengths happen to be
4-byte aligned, the reservation is too large and stale buffer content
is sent to the client.
Fix this by breaking out every encoded field explicitly in the ds_len
calculation, using xdr_align_size() for all variable-length opaque
fields, and correcting the header constants.
SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).
A fix is available. Apply it within your standard update timelines.
Exploitation none (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from Vulnrichment. EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.
In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). Where an input reads “CISA's BOD 26-04 default”, no one has published it for this CVE, and CISA's implementation guidance says: “If “Automatable” and “Technical Impact” information items about a CVE ID are not available and the CVE ID is not in the KEV Catalog, CISA will treat its values as “no” and “total,” respectively, until CISA or a third party provides metadata about the CVE ID. CISA will always provide the Vulnrichment data for a CVE ID listed in the KEV Catalog.” Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it