CVE-2026-107836
RIOT is an open-source microcontroller operating system designed for Internet of Things devices and…
- Risk score
- 52/100
- CVSS
- 7.1 v4.0
- Exploit chance (30 days)
- 0.3%
- Published
- 9 Oct 2026
Open in the live forecast Today's forecast
What to know
- What it is
- RIOT is an open-source microcontroller operating system designed for Internet of Things devices and other embedded systems. In 2026.07 and earlier, the nanoCoAP client function nanocoap_sock_get_slice() in sys/net/application_layer/nanocoap/sock.c accepts a Block2 response when _block_cb() sees the expected block numb…
- Affected
- See advisory
- Fix
- Apply the vendor's security update; see the linked advisory.
- Exploitation
- No known exploitation
Why it is Yellow
- CVSS 7.1 high
- Remotely exploitable without logging in
References
Original description
RIOT is an open-source microcontroller operating system designed for Internet of Things devices and other embedded systems. In 2026.07 and earlier, the nanoCoAP client function nanocoap_sock_get_slice() in sys/net/application_layer/nanocoap/sock.c accepts a Block2 response when _block_cb() sees the expected block number without also verifying that the server-controlled szx and derived offset match the requested block geometry. A malicious CoAP server can return the expected block number with a larger block size, causing the derived offset to exceed the client slice offset and making ctx->offset - offset underflow in _2buf_slice(). The resulting buffer-relative calculation can read before the payload buffer and crash the client, causing denial of service and potentially exposing adjacent memory. No fixed release is available as of this review.
Last activity 9 Oct 2026. Patch Forecast updates every hour.