In the Linux kernel, the following vulnerability has been resolved:
auxdisplay: line-display: fix OOB read on zero-length message_store()
linedisp_display() unconditionally reads msg[count - 1] before
checking whether count is zero, so a write of zero bytes to the
message sysfs attribute hits msg[-1]:
write(fd, "", 0);
-> message_store(..., buf, count=0)
-> linedisp_display(linedisp, buf, count=0)
-> msg[count - 1] == '\n' ; OOB read
The kernfs write buffer for that store is a 1-byte allocation
(kernfs_fop_write_iter() does kmalloc(len + 1) with len == 0),
so msg[-1] is a 1-byte read before the slab object. On a
KASAN-enabled kernel this trips an out-of-bounds report and
panics; on stock kernels it silently reads adjacent slab data
and, if that byte happens to be '\n', the following count--
wraps ssize_t 0 to -1 and is then passed to kmemdup_nul().
linedisp_display() is reached from the message_store() sysfs
callback (drivers/auxdisplay/line-display.c message attribute,
mode 0644) and from the in-tree initial-message setup with
count == -1, so the OOB path is only userspace-triggerable via
zero-byte writes; vfs_write() does not short-circuit on
count == 0 and kernfs_fop_write_iter() dispatches the store
callback regardless.
Guard the trailing-newline trim with a count check. The
existing if (!count) block then takes the clear-display path
unchanged.
Affects every auxdisplay driver that registers via
linedisp_register() / linedisp_attach(): ht16k33, max6959,
img-ascii-lcd, seg-led-gpio.
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 2026-10-29). 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: 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.
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