In the Linux kernel, the following vulnerability has been resolved:
nubus: Partially revert proc_create_single_data() conversion
The conversion to proc_create_single_data() introduced a regression
whereby reading a file in /proc/bus/nubus results in a seg fault:
# grep -r . /proc/bus/nubus/e/
Data read fault at 0x00000020 in Super Data (pc=0x1074c2)
BAD KERNEL BUSERR
Oops: 00000000
Modules linked in:
PC: [<001074c2>] PDE_DATA+0xc/0x16
SR: 2010 SP: 38284958 a2: 01152370
d0: 00000001 d1: 01013000 d2: 01002790 d3: 00000000
d4: 00000001 d5: 0008ce2e a0: 00000000 a1: 00222a40
Process grep (pid: 45, task=142f8727)
Frame format=B ssw=074d isc=2008 isb=4e5e daddr=00000020 dobuf=01199e70
baddr=001074c8 dibuf=ffffffff ver=f
Stack from 01199e48:
01199e70 00222a58 01002790 00000000 011a3000 01199eb0 015000c0 00000000
00000000 01199ec0 01199ec0 000d551a 011a3000 00000001 00000000 00018000
d003f000 00000003 00000001 0002800d 01052840 01199fa8 c01f8000 00000000
00000029 0b532b80 00000000 00000000 00000029 0b532b80 01199ee4 00103640
011198c0 d003f000 00018000 01199fa8 00000000 011198c0 00000000 01199f4c
000b3344 011198c0 d003f000 00018000 01199fa8 00000000 00018000 011198c0
Call Trace: [<00222a58>] nubus_proc_rsrc_show+0x18/0xa0
[<000d551a>] seq_read+0xc4/0x510
[<00018000>] fp_fcos+0x2/0x82
[<0002800d>] __sys_setreuid+0x115/0x1c6
[<00103640>] proc_reg_read+0x5c/0xb0
[<00018000>] fp_fcos+0x2/0x82
[<000b3344>] __vfs_read+0x2c/0x13c
[<00018000>] fp_fcos+0x2/0x82
[<00018000>] fp_fcos+0x2/0x82
[<000b8aa2>] sys_statx+0x60/0x7e
[<000b34b6>] vfs_read+0x62/0x12a
[<00018000>] fp_fcos+0x2/0x82
[<00018000>] fp_fcos+0x2/0x82
[<000b39c2>] ksys_read+0x48/0xbe
[<00018000>] fp_fcos+0x2/0x82
[<000b3a4e>] sys_read+0x16/0x1a
[<00018000>] fp_fcos+0x2/0x82
[<00002b84>] syscall+0x8/0xc
[<00018000>] fp_fcos+0x2/0x82
[<0000c016>] not_ext+0xa/0x18
Code: 4e5e 4e75 4e56 0000 206e 0008 2068 ffe8 <2068> 0020 2008 4e5e 4e75 4e56 0000 2f0b 206e 0008 2068 0004 2668 0020 206b ffe8
Disabling lock debugging due to kernel taint
Segmentation fault
The proc_create_single_data() conversion does not work because
single_open(file, nubus_proc_rsrc_show, PDE_DATA(inode)) is not
equivalent to the original code.
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 2026-11-04). 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 (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (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)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 Vulnrichment) · Technical impact total (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