In the Linux kernel, the following vulnerability has been resolved:
LoongArch: Add architecture specific huge_pte_clear()
When executing mm selftests run_vmtests.sh, there is such an error:
BUG: Bad page state in process uffd-unit-tests pfn:00000
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x0
flags: 0xffff0000002000(reserved|node=0|zone=0|lastcpupid=0xffff)
raw: 00ffff0000002000 ffffbf0000000008 ffffbf0000000008 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: PAGE_FLAGS_CHECK_AT_FREE flag(s) set
Modules linked in: snd_seq_dummy snd_seq snd_seq_device rfkill vfat fat
virtio_balloon efi_pstore virtio_net pstore net_failover failover fuse
nfnetlink virtio_scsi virtio_gpu virtio_dma_buf dm_multipath efivarfs
CPU: 2 UID: 0 PID: 1913 Comm: uffd-unit-tests Not tainted 6.12.0 #184
Hardware name: QEMU QEMU Virtual Machine, BIOS unknown 2/2/2022
Stack : 900000047c8ac000 0000000000000000 9000000000223a7c 900000047c8ac000
900000047c8af690 900000047c8af698 0000000000000000 900000047c8af7d8
900000047c8af7d0 900000047c8af7d0 900000047c8af5b0 0000000000000001
0000000000000001 900000047c8af698 10b3c7d53da40d26 0000010000000000
0000000000000022 0000000fffffffff fffffffffe000000 ffff800000000000
000000000000002f 0000800000000000 000000017a6d4000 90000000028f8940
0000000000000000 0000000000000000 90000000025aa5e0 9000000002905000
0000000000000000 90000000028f8940 ffff800000000000 0000000000000000
0000000000000000 0000000000000000 9000000000223a94 000000012001839c
00000000000000b0 0000000000000004 0000000000000000 0000000000071c1d
...
Call Trace:
[<9000000000223a94>] show_stack+0x5c/0x180
[<9000000001c3fd64>] dump_stack_lvl+0x6c/0xa0
[<900000000056aa08>] bad_page+0x1a0/0x1f0
[<9000000000574978>] free_unref_folios+0xbf0/0xd20
[<90000000004e65cc>] folios_put_refs+0x1a4/0x2b8
[<9000000000599a0c>] free_pages_and_swap_cache+0x164/0x260
[<9000000000547698>] tlb_batch_pages_flush+0xa8/0x1c0
[<9000000000547f30>] tlb_finish_mmu+0xa8/0x218
[<9000000000543cb8>] exit_mmap+0x1a0/0x360
[<9000000000247658>] __mmput+0x78/0x200
[<900000000025583c>] do_exit+0x43c/0xde8
[<9000000000256490>] do_group_exit+0x68/0x110
[<9000000000256554>] sys_exit_group+0x1c/0x20
[<9000000001c413b4>] do_syscall+0x94/0x130
[<90000000002216d8>] handle_syscall+0xb8/0x158
Disabling lock debugging due to kernel taint
BUG: non-zero pgtables_bytes on freeing mm: -16384
On LoongArch system, invalid huge pte entry should be invalid_pte_table
or a single _PAGE_HUGE bit rather than a zero value. And it should be
the same with invalid pmd entry, since pmd_none() is called by function
free_pgd_range() and pmd_none() return 0 by huge_pte_clear(). So single
_PAGE_HUGE bit is also treated as a valid pte table and free_pte_range()
will be called in free_pmd_range().
free_pmd_range()
pmd = pmd_offset(pud, addr);
do {
next = pmd_addr_end(addr, end);
if (pmd_none_or_clear_bad(pmd))
continue;
free_pte_range(tlb, pmd, addr);
} while (pmd++, addr = next, addr != end);
Here invalid_pte_table is used for both invalid huge pte entry and
pmd entry.
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (7.8): severity, escalated by confirmed exploitation. This CVE's 7.8 is its impact severity (EG Severity), not escalated.
- EG Severity
- 7.8 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
- EG Likelihood
- 0.2% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-03). 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
- SSVC Track at medium mission impactTrack at low or medium mission impact; Track* at high (mission-essential systems).CISA 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 SSVC and BOD 26-04 blocks below.
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.
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