In the Linux kernel, the following vulnerability has been resolved:
drivers: perf: Check find_first_bit() return value
We must check the return value of find_first_bit() before using the
return value as an index array since it happens to overflow the array
and then panic:
[ 107.318430] Kernel BUG [#1]
[ 107.319434] CPU: 3 PID: 1238 Comm: kill Tainted: G E 6.6.0-rc6ubuntu-defconfig #2
[ 107.319465] Hardware name: riscv-virtio,qemu (DT)
[ 107.319551] epc : pmu_sbi_ovf_handler+0x3a4/0x3ae
[ 107.319840] ra : pmu_sbi_ovf_handler+0x52/0x3ae
[ 107.319868] epc : ffffffff80a0a77c ra : ffffffff80a0a42a sp : ffffaf83fecda350
[ 107.319884] gp : ffffffff823961a8 tp : ffffaf8083db1dc0 t0 : ffffaf83fecda480
[ 107.319899] t1 : ffffffff80cafe62 t2 : 000000000000ff00 s0 : ffffaf83fecda520
[ 107.319921] s1 : ffffaf83fecda380 a0 : 00000018fca29df0 a1 : ffffffffffffffff
[ 107.319936] a2 : 0000000001073734 a3 : 0000000000000004 a4 : 0000000000000000
[ 107.319951] a5 : 0000000000000040 a6 : 000000001d1c8774 a7 : 0000000000504d55
[ 107.319965] s2 : ffffffff82451f10 s3 : ffffffff82724e70 s4 : 000000000000003f
[ 107.319980] s5 : 0000000000000011 s6 : ffffaf8083db27c0 s7 : 0000000000000000
[ 107.319995] s8 : 0000000000000001 s9 : 00007fffb45d6558 s10: 00007fffb45d81a0
[ 107.320009] s11: ffffaf7ffff60000 t3 : 0000000000000004 t4 : 0000000000000000
[ 107.320023] t5 : ffffaf7f80000000 t6 : ffffaf8000000000
[ 107.320037] status: 0000000200000100 badaddr: 0000000000000000 cause: 0000000000000003
[ 107.320081] [] pmu_sbi_ovf_handler+0x3a4/0x3ae
[ 107.320112] [] handle_percpu_devid_irq+0x9e/0x1a0
[ 107.320131] [] generic_handle_domain_irq+0x28/0x36
[ 107.320148] [] riscv_intc_irq+0x36/0x4e
[ 107.320166] [] handle_riscv_irq+0x54/0x86
[ 107.320189] [] do_irq+0x64/0x96
[ 107.320271] Code: 85a6 855e b097 ff7f 80e7 9220 b709 9002 4501 bbd9 (9002) 6097
[ 107.320585] ---[ end trace 0000000000000000 ]---
[ 107.320704] Kernel panic - not syncing: Fatal exception in interrupt
[ 107.320775] SMP: stopping secondary CPUs
[ 107.321219] Kernel Offset: 0x0 from 0xffffffff80000000
[ 107.333051] ---[ end Kernel panic - not syncing: Fatal exception in interrupt ]---
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
- 0.3% 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