In the Linux kernel, the following vulnerability has been resolved:
libceph: fix multiple unsafe decodes in decode_locker()
decode_locker() in cls_lock_client.c contains three unsafe decode
operations that allow a malicious or compromised OSD to trigger
slab-out-of-bounds reads:
- ceph_decode_copy() at the locker_id_t name field has no preceding
bounds check. With p == end after ceph_start_decoding() accepts
struct_len=0, this reads sizeof(ceph_entity_name) = 9 bytes past
the validated buffer boundary.
- *p += sizeof(struct ceph_timespec) after the locker_info_t header
is an unchecked pointer advance. A malicious OSD can position p
past end, causing all subsequent _safe checks to pass against a
bogus boundary.
- len = ceph_decode_32(p) has no preceding bounds check, and the
immediately following *p += len is uncapped. A malicious OSD can
send len=0xffffffff, advancing p gigabytes past end and escaping
the decode window entirely.
Fix all three by replacing bare operations with their safe variants:
ceph_decode_copy -> ceph_decode_copy_safe
*p += sizeof(...) -> ceph_decode_skip_n
ceph_decode_32(p) -> ceph_decode_32_safe
*p += len -> ceph_decode_skip_n
A new label is added to return -EINVAL on any bounds violation.
-EINVAL is appropriate here: the data received from the OSD
is structurally malformed, which is an invalid argument to the decode
contract regardless of whether the caller or the wire is at fault.
Attacker model: a malicious or compromised OSD in a multi-tenant Ceph
deployment can trigger this against any kernel client that issues the
lock.get_info class method (e.g. during RBD exclusive lock acquisition)
without any further privileges beyond OSD session establishment.
[ idryomov: use ceph_decode_skip_string() to skip description, trim
changelog ]
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