In the Linux kernel, the following vulnerability has been resolved:
virtio_pmem: add the missing REQ_OP_WRITE for flush bio
When doing mkfs.xfs on a pmem device, the following warning was
------------[ cut here ]------------
WARNING: CPU: 2 PID: 384 at block/blk-core.c:751 submit_bio_noacct
Modules linked in:
CPU: 2 PID: 384 Comm: mkfs.xfs Not tainted 6.4.0-rc7+ #154
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
RIP: 0010:submit_bio_noacct+0x340/0x520
......
Call Trace:
? submit_bio_noacct+0xd5/0x520
submit_bio+0x37/0x60
async_pmem_flush+0x79/0xa0
nvdimm_flush+0x17/0x40
pmem_submit_bio+0x370/0x390
__submit_bio+0xbc/0x190
submit_bio_noacct_nocheck+0x14d/0x370
submit_bio_noacct+0x1ef/0x520
submit_bio+0x55/0x60
submit_bio_wait+0x5a/0xc0
blkdev_issue_flush+0x44/0x60
The root cause is that submit_bio_noacct() needs bio_op() is either
WRITE or ZONE_APPEND for flush bio and async_pmem_flush() doesn't assign
REQ_OP_WRITE when allocating flush bio, so submit_bio_noacct just fail
the flush bio.
Simply fix it by adding the missing REQ_OP_WRITE for flush bio. And we
could fix the flush order issue and do flush optimization later.
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
- EG Severity
- Not assessed: no CVSS publishedA missing CVSS is not a severity of zero.
- EG Likelihood
- 0.2% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-26). 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
- No SSVC decision: EchelonGraph has not assessed this CVECISA 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 BOD 26-04 block below.
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's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). Where an input reads “CISA's BOD 26-04 default”, no one has published it for this CVE, and CISA's implementation guidance says: “If “Automatable” and “Technical Impact” information items about a CVE ID are not available and the CVE ID is not in the KEV Catalog, CISA will treat its values as “no” and “total,” respectively, until CISA or a third party provides metadata about the CVE ID. CISA will always provide the Vulnrichment data for a CVE ID listed in the KEV Catalog.” 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