EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
- •No CVSS published and no exploitation signals yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS v2: —Exploit: None knownExposed services: Not assessed
No fix is confirmed yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for the fix.
The CVE record's CNA (kernel.org) lists Linux versions 6.18.53 up to but not including 6.18.57 and 7.2.7 up to but not including 7.2.11 as affected. No release containing a fix is confirmed on record.
In the Linux kernel, the following vulnerability has been resolved:
mm: don't schedule deferred kernel page table freeing while booting
Booting with a boot-time function tracer and a filter, for example
ftrace=function ftrace_filter=pud_free_pmd_page
panics on 7.3-rc4 as soon as the tracer starts:
[ 23.531178] Starting tracer 'function'
[ 23.675800] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000038: 0000 [#1] SMP KASAN NOPTI
[ 23.819917] KASAN: null-ptr-deref in range [0x00000000000001c0-0x00000000000001c7]
[ 23.964025] CPU: 0 UID: 0 PID: 0 Comm: swapper Not tainted 7.3.0-rc4-fe2ec83746e5-with-fixes-v2+ #195 PREEMPT(undef)
[ 24.252248] RIP: 0010:__queue_work+0xab/0xf00
[ 25.981629] Call Trace:
[ 26.125727]
[ 26.413912] ? pagetable_free_kernel+0x20/0x120
[ 26.990283] queue_work_on+0x97/0xf0
[ 27.134382] __cpa_collapse_large_pages+0x501/0x6f0
[ 27.566662] cpa_flush+0x394/0x620
[ 27.998953] change_page_attr_set_clr+0x321/0x4a0
[ 29.151729] set_memory_rox+0xa2/0xf0
[ 29.584018] create_trampoline+0x431/0x6f0
...
[ 44.343347] Kernel panic - not syncing: Attempted to kill the idle task!
The boot-time tracer is started from early_trace_init(), which runs
before workqueue_init_early(). Making its trampoline read-only splits a
large page, and CPA collapses it again right away. The split table has
been a kernel page table since commit 9e4a3ec3411b
("x86/mm/pat: Allocate split page tables as kernel page tables"), so the
collapse frees it through pagetable_free_kernel(), which queues work on
system_percpu_wq - still NULL at that point. That commit is correct in
itself; it only lets CPA reach pagetable_free_kernel() before the
workqueue that function relies on exists.
Keep putting the table on the list, but don't schedule the work while
the system is still booting. A core_initcall schedules it once to free
whatever was queued by then.
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.No released fix is confirmed on this page, but CISA's timeline does not wait for a fix's release: it starts when an agency identifies the flaw on an asset and updates the CDM Agency and Federal Dashboard, and the directive counts patching, decommissioning the system or another action as remediation. Until a fixed release is applied, mitigate as this page's verdict says. In the directive's words, “Fix on system upgrade” means that, “unless conditions change”, the vulnerability “should be remediated the next time the vulnerable asset receives a scheduled major upgrade or rebuild”: its timelines are “dynamic as facts change”, and a KEV listing shortens them.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.
No released fix is confirmed on this page, but CISA's timeline does not wait for a fix's release: it starts when an agency identifies the flaw on an asset and updates the CDM Agency and Federal Dashboard, and the directive counts patching, decommissioning the system or another action as remediation. Until a fixed release is applied, mitigate as this page's verdict says. In the directive's words, “Fix on system upgrade” means that, “unless conditions change”, the vulnerability “should be remediated the next time the vulnerable asset receives a scheduled major upgrade or rebuild”: its timelines are “dynamic as facts change”, and a KEV listing shortens them.
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