In the Linux kernel, the following vulnerability has been resolved:
iommufd: Fix protection fault in iommufd_test_syz_conv_iova
Syzkaller reported the following bug:
general protection fault, probably for non-canonical address 0xdffffc0000000038: 0000 [#1] SMP KASAN
KASAN: null-ptr-deref in range [0x00000000000001c0-0x00000000000001c7]
Call Trace:
lock_acquire
lock_acquire+0x1ce/0x4f0
down_read+0x93/0x4a0
iommufd_test_syz_conv_iova+0x56/0x1f0
iommufd_test_access_rw.isra.0+0x2ec/0x390
iommufd_test+0x1058/0x1e30
iommufd_fops_ioctl+0x381/0x510
vfs_ioctl
__do_sys_ioctl
__se_sys_ioctl
__x64_sys_ioctl+0x170/0x1e0
do_syscall_x64
do_syscall_64+0x71/0x140
This is because the new iommufd_access_change_ioas() sets access->ioas to
NULL during its process, so the lock might be gone in a concurrent racing
context.
Fix this by doing the same access->ioas sanity as iommufd_access_rw() and
iommufd_access_pin_pages() functions do.
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