← Vulnerability feed

Vulnerability record · CVE-2026-5855 · published 6 August 2026

CVE-2026-5855: Out-of-bounds read vulnerability

Contiki-NG's LwM2M TLV parser lwm2m_tlv_read() in os/services/lwm2m/lwm2m-tlv.c ignores its caller-supplied buffer length argument and reads up to six bytes from the input buffer with no bounds check. The caller in lwm2m-engine.c iterates while there is at least one byte remaining, so a crafted CoAP WRITE to any LwM2M endpoint whose final TLV supplies exactly one byte triggers up to five out-of-bounds reads of heap memory adjacent to the CoAP input buffer, disclosing memory contents (including key material and peer addresses) through the parsed tlv->id, tlv->length, and tlv->value fields. Corrupted tlv_len derived from the out-of-bounds memory further corrupts the caller's parse offset. In LwM2M NoSec mode, the default for constrained devices, no authentication is required.

8.7 CVSS 4.0 High EPSS 0.72% · top 48.1% CWE-125 · Out-of-bounds read Deferred
8.7CVSS 4.0 base score
0.72%EPSS exploitation probability, 30 days
NoNot in CISA KEV
0Affected product versions listed by NVD
3References
16 Sep 2026Last modified by NVD

Description

Contiki-NG's LwM2M TLV parser lwm2m_tlv_read() in os/services/lwm2m/lwm2m-tlv.c ignores its caller-supplied buffer length argument and reads up to six bytes from the input buffer with no bounds check. The caller in lwm2m-engine.c iterates while there is at least one byte remaining, so a crafted CoAP WRITE to any LwM2M endpoint whose final TLV supplies exactly one byte triggers up to five out-of-bounds reads of heap memory adjacent to the CoAP input buffer, disclosing memory contents (including key material and peer addresses) through the parsed tlv->id, tlv->length, and tlv->value fields. Corrupted tlv_len derived from the out-of-bounds memory further corrupts the caller's parse offset. In LwM2M NoSec mode, the default for constrained devices, no authentication is required.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/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:

References

LinkTags
https://github.com/contiki-ng/contiki-ng
https://github.com/contiki-ng/contiki-ng/commit/f1673b5766d4d4d514cefb8a0350f43653574997
https://github.com/contiki-ng/contiki-ng/pull/3165

Track CVE-2026-5855 inside VULONE

Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.

Start free Open in platform

Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

8.8CVE-2026-11645Google Chrome V8 out-of-bounds read and write enables sandbox code executionGoogle Chrome before 149.0.7827.103 contains an out-of-bounds read and write in the V8 JavaScript engine. A crafted HTML page can trigger the memory …KEVEPSS 2.2%analysed7.8CVE-2023-36424Windows Common Log File System Driver out-of-bounds read privilege escalationCVE-2023-36424 is an out-of-bounds read (CWE-125) in the Windows Common Log File System (CLFS) driver that allows elevation of privilege. It affects …KEVEPSS 12%analysed9.3CVE-2026-3055Citrix NetScaler ADC and Gateway SAML IDP memory overreadNetScaler ADC and NetScaler Gateway, when configured as a SAML identity provider, fail to validate input sufficiently, causing an out-of-bounds memor…KEVEPSS 4.0%analysed9.3CVE-2025-5777Citrix NetScaler ADC/Gateway memory overread via insufficient input validationCVE-2025-5777 is an insufficient input validation flaw in Citrix NetScaler ADC and NetScaler Gateway that causes a memory overread when the appliance…KEVEPSS 100%analysed8.8CVE-2025-5419Google Chrome V8 out-of-bounds read and write enables heap corruptionV8 in Google Chrome before 137.0.7151.68 contains an out-of-bounds read and write that a remote attacker can trigger with a crafted HTML page, leadin…KEVEPSS 7.8%analysed7.1CVE-2024-53150Linux kernel ALSA USB-audio out-of-bounds read in clock descriptor parsingThe Linux kernel ALSA USB-audio driver fails to validate the bLength field of clock descriptors while traversing them, so a device supplying a malfor…KEVEPSS 1.4%analysed5.5CVE-2025-24991Windows NTFS out-of-bounds read allows local information disclosureWindows NTFS contains an out-of-bounds read (CWE-125) that lets an authorized attacker disclose information locally. The flaw is rated CVSS 3.1 5.5 (…KEVEPSS 2.0%analysed6.0CVE-2025-22226VMware ESXi, Workstation and Fusion HGFS out-of-bounds read leaks vmx memoryVMware ESXi, Workstation, Fusion and related cloud products contain an out-of-bounds read in the HGFS (Host Guest File System) component. A malicious…KEVEPSS 1.7%analysed

Source: NIST National Vulnerability Database (record CVE-2026-5855), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.