In the Linux kernel, the following vulnerability has been resolved:
netlink: avoid hashing the network namespace pointer
The netlink rhashtable key includes a raw struct net pointer and a
user-controlled port ID. Both /proc/net/netlink and socket diagnostics
expose the table's bucket order. By binding and rebinding chosen
NETLINK_USERSOCK port IDs, an unprivileged reader can distinguish equal
buckets and recover the low bits of the Jenkins hash. Its 32-bit seed
and the limited set of kernel-image slides can then be searched offline
to recover the address of init_net.
Use the namespace's unique, non-address net_cookie in the comparison
key instead. It is assigned before the per-net initializers run and
remains unchanged for the namespace's lifetime. The lookup key and
object hash are still built by netlink_compare_arg_init(), keeping
lookup, insertion, removal and rehashing consistent while preserving
namespace separation. Neither public table walker needs to change.
Reading the socket's namespace cookie in netlink_compare() is safe
under RCU, including during namespace teardown. netlink_release()
removes the socket from the hash table and defers its final put with
call_rcu(). cleanup_net() runs the per-net exit methods and waits for
outstanding RCU callbacks with rcu_barrier() before freeing namespace
storage.
Unlike ns.ns_id, net_cookie is also available and initialized during
setup_net() in older stable kernels, making the change straightforward
to backport to v5.15 and later.
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
- EG Severity
- Not assessed: no CVSS publishedA missing CVSS is not a severity of zero.
- EG Likelihood
- 0.2% within 30 daysSource: FIRST EPSS. FIRST's exploitation probability, not an EchelonGraph model.
- Confirmed exploitation
- None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
- EG Priority
- No SSVC decision: EchelonGraph has not assessed this CVECISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the BOD 26-04 block below.
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.
The score's inputs: 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