In the Linux kernel, the following vulnerability has been resolved:
powerpc/pseries: Whitelist dtl slub object for copying to userspace
Reading the dispatch trace log from /sys/kernel/debug/powerpc/dtl/cpu-*
results in a BUG() when the config CONFIG_HARDENED_USERCOPY is enabled as
shown below.
kernel BUG at mm/usercopy.c:102!
Oops: Exception in kernel mode, sig: 5 [#1]
LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA pSeries
Modules linked in: xfs libcrc32c dm_service_time sd_mod t10_pi sg ibmvfc
scsi_transport_fc ibmveth pseries_wdt dm_multipath dm_mirror dm_region_hash dm_log dm_mod fuse
CPU: 27 PID: 1815 Comm: python3 Not tainted 6.10.0-rc3 #85
Hardware name: IBM,9040-MRX POWER10 (raw) 0x800200 0xf000006 of:IBM,FW1060.00 (NM1060_042) hv:phyp pSeries
NIP: c0000000005d23d4 LR: c0000000005d23d0 CTR: 00000000006ee6f8
REGS: c000000120c078c0 TRAP: 0700 Not tainted (6.10.0-rc3)
MSR: 8000000000029033 CR: 2828220f XER: 0000000e
CFAR: c0000000001fdc80 IRQMASK: 0
[ ... GPRs omitted ... ]
NIP [c0000000005d23d4] usercopy_abort+0x78/0xb0
LR [c0000000005d23d0] usercopy_abort+0x74/0xb0
Call Trace:
usercopy_abort+0x74/0xb0 (unreliable)
__check_heap_object+0xf8/0x120
check_heap_object+0x218/0x240
__check_object_size+0x84/0x1a4
dtl_file_read+0x17c/0x2c4
full_proxy_read+0x8c/0x110
vfs_read+0xdc/0x3a0
ksys_read+0x84/0x144
system_call_exception+0x124/0x330
system_call_vectored_common+0x15c/0x2ec
--- interrupt: 3000 at 0x7fff81f3ab34
Commit 6d07d1cd300f ("usercopy: Restrict non-usercopy caches to size 0")
requires that only whitelisted areas in slab/slub objects can be copied to
userspace when usercopy hardening is enabled using CONFIG_HARDENED_USERCOPY.
Dtl contains hypervisor dispatch events which are expected to be read by
privileged users. Hence mark this safe for user access.
Specify useroffset=0 and usersize=DISPATCH_LOG_BYTES to whitelist the
entire object.
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (5.5): severity, escalated by confirmed exploitation. This CVE's 5.5 is its impact severity (EG Severity), not escalated.
- EG Severity
- 5.5 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