In the Linux kernel, the following vulnerability has been resolved:
arm64: extable: fix load_unaligned_zeropad() reg indices
In ex_handler_load_unaligned_zeropad() we erroneously extract the data and
addr register indices from ex->type rather than ex->data. As ex->type will
contain EX_TYPE_LOAD_UNALIGNED_ZEROPAD (i.e. 4):
* We'll always treat X0 as the address register, since EX_DATA_REG_ADDR is
extracted from bits [9:5]. Thus, we may attempt to dereference an
arbitrary address as X0 may hold an arbitrary value.
* We'll always treat X4 as the data register, since EX_DATA_REG_DATA is
extracted from bits [4:0]. Thus we will corrupt X4 and cause arbitrary
behaviour within load_unaligned_zeropad() and its caller.
Fix this by extracting both values from ex->data as originally intended.
On an MTE-enabled QEMU image we are hitting the following crash:
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
Call trace:
fixup_exception+0xc4/0x108
__do_kernel_fault+0x3c/0x268
do_tag_check_fault+0x3c/0x104
do_mem_abort+0x44/0xf4
el1_abort+0x40/0x64
el1h_64_sync_handler+0x60/0xa0
el1h_64_sync+0x7c/0x80
link_path_walk+0x150/0x344
path_openat+0xa0/0x7dc
do_filp_open+0xb8/0x168
do_sys_openat2+0x88/0x17c
__arm64_sys_openat+0x74/0xa0
invoke_syscall+0x48/0x148
el0_svc_common+0xb8/0xf8
do_el0_svc+0x28/0x88
el0_svc+0x24/0x84
el0t_64_sync_handler+0x88/0xec
el0t_64_sync+0x1b4/0x1b8
Code: f8695a69 71007d1f 540000e0 927df12a (f940014a)
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (6.2): severity, escalated by confirmed exploitation. This CVE's 6.2 is its impact severity (EG Severity), not escalated.
- EG Severity
- 6.2 MEDIUMCVSS-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 2026-10-25). 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 every mission impact level.CISA BOD 26-04: 60 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 every mission impact level.
A fix is available. Apply it within your standard update timelines.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (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)60 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 Vulnrichment) · Technical impact partial (CISA Vulnrichment). 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