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TI-2026-05134 Aliases CVE-2026-5855GHSA-ch5q-j8ff-mq34

Contiki-NG LwM2M TLV Parser Out-of-Bounds Read via Unchecked Buffer Length in lwm2m_tlv_read

Priority MEDIUM 45CWE-125Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-125 and the CVSS impact.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00718 54th percentileScored 2026-11-07
Fix Fixed Contiki-NG (Contiki-NG): f1673b5766d4d4d514cefb8a0350f43653574997

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
contiki-ngContiki-NGbefore f1673b5766d4d4d514cefb8a0350f43653574997f1673b5766d4d4d514cefb8a0350f43653574997Patch availableCNA
  • Contiki-NG Vendorcontiki-ng Affected before f1673b5766d4d4d514cefb8a0350f43653574997 Fixed in f1673b5766d4d4d514cefb8a0350f43653574997 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:o:contiki-ng:contiki-ng:*:*:*:*:*:*:*:*——contiki-ng
  • cpe:2.3:o:contiki-ng:contiki-ng:*:*:*:*:*:*:*:* Versions — — ·contiki-ng

Remediation

  • Fix · CNA Contiki-NG (Contiki-NG) Fixed in f1673b5766d4d4d514cefb8a0350f43653574997

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-5855
  2. 2026-10-03 Alias added: GHSA-ch5q-j8ff-mq34

References

Patch 2

Other 1

  • TI-2020-14885 An issue was discovered in Contiki through 3.0 and Contiki-NG through 4.5. CVSS 3.1CRITICAL 9.8
  • TI-2021-18649 An issue was discovered in Contiki-NG tinyDTLS through master branch 53a0d97. CVSS 3.1CRITICAL 9.8
  • TI-2020-16751 In Contiki 4.5, TCP ISNs are improperly random. CVSS 3.1CRITICAL 9.1
  • TI-2018-16029 contiki-ng version 4 contains a Buffer Overflow vulnerability in AQL (Antelope Query… CVSS 3.1CRITICAL 9.8
  • TI-2018-13749 An issue was discovered in the MQTT server in Contiki-NG before 4.2. CVSS 3.0CRITICAL 10.0
  • TI-2023-14381 Contiki-NG has off-by-one error in Antelope DBMS CVSS 3.1CRITICAL 9.8
See all 56 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences