RIOT-OS RIOT up to 2026.01 well_known_core out-of-bounds write

CVSS Meta Temp Score
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CTI Interest Score
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8.1$0-$5k0.00

Summaryinfo

A vulnerability described as critical has been identified in RIOT-OS RIOT up to 2026.01. Affected is the function well_known_core. Such manipulation leads to out-of-bounds write. This vulnerability is listed as CVE-2026-27703. The attack may be performed from remote. There is no available exploit. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in RIOT-OS RIOT up to 2026.01. It has been rated as critical. Affected by this issue is the function well_known_core. The manipulation with an unknown input leads to a out-of-bounds write vulnerability. Using CWE to declare the problem leads to CWE-787. The product writes data past the end, or before the beginning, of the intended buffer. Impacted is confidentiality, integrity, and availability. CVE summarizes:

RIOT is an open-source microcontroller operating system, designed to match the requirements of Internet of Things (IoT) devices and other embedded devices. In 2026.01 and earlier, the default handler for the well_known_core resource coap_well_known_core_default_handler writes user-provided option data and other data into a fixed size buffer without validating the buffer is large enough to contain the response. This vulnerability allows an attacker to corrupt neighboring stack location, including security-sensitive addresses like the return address, leading to denial of service or arbitrary code execution.

The advisory is available at github.com. This vulnerability is handled as CVE-2026-27703 since 02/23/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. Technical details are known, but there is no available exploit.

Upgrading eliminates this vulnerability.

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Productinfo

Vendor

Name

Version

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.2
VulDB Meta Temp Score: 8.1

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 9.8
NVD Vector: 🔒

CNA Base Score: 7.5
CNA Vector (GitHub_M): 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Out-of-bounds write
CWE: CWE-787 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Timelineinfo

02/23/2026 CVE reserved
03/11/2026 +16 days Advisory disclosed
03/11/2026 +0 days VulDB entry created
03/17/2026 +6 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: github.com
Status: Confirmed

CVE: CVE-2026-27703 (🔒)
GCVE (CVE): GCVE-0-2026-27703
GCVE (VulDB): GCVE-100-350558

Entryinfo

Created: 03/11/2026 21:02
Updated: 03/17/2026 04:17
Changes: 03/11/2026 21:02 (63), 03/14/2026 19:22 (1), 03/17/2026 04:17 (11)
Complete: 🔍
Cache ID: 216::103

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