RIOT OS <= 2026.01-devel-317 Stack-Based Buffer Overflow in ethos Serial Frame Parser

published 2026-01-12 9 mo ago modified 2026-07-14 3 mo ago also EUVD-2026-2395

cvss: 9.8; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 0.5%; EPSS 0.5% chance of exploitation in 30 days, percentile 40%
public exploits: 0; none known

RIOT OS versions up to and including 2026.01-devel-317 contain a stack-based buffer overflow vulnerability in the ethos utility due to missing bounds checking when processing incoming serial frame data. The vulnerability occurs in the _handle_char() function, where incoming frame bytes are appended to a fixed-size stack buffer without verifying that the current write index remains within bounds. An attacker capable of sending crafted serial or TCP-framed input can cause the current write index to exceed the buffer size, resulting in a write past the end of the stack buffer. This condition leads to memory corruption and application crash.

Patch / fix

fixed in 1

riot-os riot 2025.10

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: partial
Assessed: 9 mo ago (2026-01-13)

Exploit prediction

0.46% chance of exploitation in the next 30 days, higher than 40% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

seclists.org https://seclists.org/fulldisclosure/2026/Jan/16 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	4.0	6.8	CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CNA	4.0	6.8	CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD	3.1	9.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

RIOT RIOT OS

Classification

Weakness

CWE-121 Stack-based Buffer Overflow

References

seclists.org /fulldisclosure/2026/Jan/16
technical-description, exploit, mailing-list, third-party-advisory
riot-os.org /
product
github.com /RIOT-OS/RIOT
product
vulncheck.com /advisories/riot-os-stack-based-buffer-overflow-in-ethos-serial-frame-parser
third-party-advisory

Sources

CVE List CVE-2026-22214
NVD CVE-2026-22214

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary