In the Linux kernel, the following vulnerability has been resolved:
USB: serial: option: fix slab OOB read in interrupt URB callback
The interrupt URB buffer is allocated in setup_port_interrupt_in() based
on the endpoint's wMaxPacketSize:
buffer_size = usb_endpoint_maxp(epd);
port->interrupt_in_buffer = kmalloc(buffer_size, GFP_KERNEL);
When a USB device declares wMaxPacketSize = 8 on its interrupt IN
endpoint, the buffer is allocated from kmalloc-8 cache (exactly
8 bytes).
If the device sends a short packet (actual_length < wMaxPacketSize),
the URB completes with status == 0 and the callback proceeds to read:
data[sizeof(struct usb_ctrlrequest)]
which evaluates to data[8], accessing 1 byte beyond the allocated 8-byte
buffer. This results in a slab out-of-bounds read.
Fix this by adding the missing bounds check: first verify that the
actual length is large enough to contain the struct usb_ctrlrequest
header before accessing req_pkt->bRequestType and req_pkt->bRequest,
and then verify that there is an additional byte for the modem signal
state before reading data[sizeof(struct usb_ctrlrequest)] inside the
conditional. Use sizeof(*req_pkt) instead of sizeof(struct
usb_ctrlrequest) for consistency.
[ johan: use dev_err(); split signals declaration and initialisation ]
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 2026-10-24). 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