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01 Record

CVE-2026-5856

Contiki-NG DNS/mDNS Resolver Out-of-Bounds Read via Unchecked skip_name Traversal Before Transaction-ID Validation

HighPUBLISHEDCNA: VulnCheck
CNA base score7.1 CVSS v4.0CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:L/SC:N/SI:N/SA:N

02 Description

Contiki-NG DNS/mDNS Resolver Out-of-Bounds Read via Unchecked skip_name Traversal Before Transaction-ID Validation

03 Exploitation and scoring

Exploitation
Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.
SSVC decision
  • ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
  • AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
  • Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.
CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.
EPSS probability
0.29% probability of exploitation activity in the next 30 days.
EPSS percentile
Equal to or higher than the score of 21.4% of scored records. A rank, not a probability.
NVD base score
7.1 (CVSS v4.0), scored by the NVD independently of the CNA.
NVD CVSS vector
CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:L/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 analysis status
Deferred. NVD last modified this record on 2026-09-16.
Red Hat severity
No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

04 Metadata

Published
2026-08-06 18:47Z2 MO AGO
Last updated
2026-08-14 16:50Z2 MO AGO
Reserved
2026-04-08
Assigning CNA
VulnCheck
Record state
PUBLISHED
Severity
High (CVSS 7.1)
CNA CVSS vector
CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:L/SC:N/SI:N/SA:N
Weaknesses
Data version
5.2
Document digest
57ccc128f0ccf5c3bce0989f88f299f55e4e49f271bdb4053b10aa2158f159d4

05 Affected products

VendorProductVersionsPlatforms
Contiki-NGContiki-NG0 to < 04a3f0a0067d2ee87d1f297b6d0f4392d8c98ffe—

06 References