In the Linux kernel, the following vulnerability has been resolved:
IB/hfi1: Fix bugs with non-PAGE_SIZE-end multi-iovec user SDMA requests
hfi1 user SDMA request processing has two bugs that can cause data
corruption for user SDMA requests that have multiple payload iovecs
where an iovec other than the tail iovec does not run up to the page
boundary for the buffer pointed to by that iovec.a
Here are the specific bugs:
- user_sdma_txadd() does not use struct user_sdma_iovec->iov.iov_len.
Rather, user_sdma_txadd() will add up to PAGE_SIZE bytes from iovec
to the packet, even if some of those bytes are past
iovec->iov.iov_len and are thus not intended to be in the packet.
- user_sdma_txadd() and user_sdma_send_pkts() fail to advance to the
next iovec in user_sdma_request->iovs when the current iovec
is not PAGE_SIZE and does not contain enough data to complete the
packet. The transmitted packet will contain the wrong data from the
iovec pages.
This has not been an issue with SDMA packets from hfi1 Verbs or PSM2
because they only produce iovecs that end short of PAGE_SIZE as the tail
iovec of an SDMA request.
Fixing these bugs exposes other bugs with the SDMA pin cache
(struct mmu_rb_handler) that get in way of supporting user SDMA requests
with multiple payload iovecs whose buffers do not end at PAGE_SIZE. So
this commit fixes those issues as well.
Here are the mmu_rb_handler bugs that non-PAGE_SIZE-end multi-iovec
payload user SDMA requests can hit:
- Overlapping memory ranges in mmu_rb_handler will result in duplicate
pinnings.
- When extending an existing mmu_rb_handler entry (struct mmu_rb_node),
the mmu_rb code (1) removes the existing entry under a lock, (2)
releases that lock, pins the new pages, (3) then reacquires the lock
to insert the extended mmu_rb_node.
If someone else comes in and inserts an overlapping entry between (2)
and (3), insert in (3) will fail.
The failure path code in this case unpins _all_ pages in either the
original mmu_rb_node or the new mmu_rb_node that was inserted between
(2) and (3).
- In hfi1_mmu_rb_remove_unless_exact(), mmu_rb_node->refcount is
incremented outside of mmu_rb_handler->lock. As a result, mmu_rb_node
could be evicted by another thread that gets mmu_rb_handler->lock and
checks mmu_rb_node->refcount before mmu_rb_node->refcount is
incremented.
- Related to #2 above, SDMA request submission failure path does not
check mmu_rb_node->refcount before freeing mmu_rb_node object.
If there are other SDMA requests in progress whose iovecs have
pointers to the now-freed mmu_rb_node(s), those pointers to the
now-freed mmu_rb nodes will be dereferenced when those SDMA requests
complete.
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
- 0.3% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-20). 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: 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.
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