CVE-2026-13351Public exploitNetwork attack vector

Network denial of service via leaked RX buffers

Published Jun 25, 2026 · Updated Jun 25, 2026

Denial of service in Zephyr RTOS 4.3 and earlier allows remote attackers to stop inbound traffic with fragmented IPv6 packets. The net_ipv6_handle_fragment_hdr path returns without unreferencing the received packet, so its RX memory-slab block is never freed. A few packets exhaust the finite RX pool on IPv6-fragmentation-enabled devices, preventing further packet reception without altering or disclosing data.

CVSS severity7.5
High
EPSS probability0.49%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Zephyr RTOS 4.3 and earlier allows remote attackers to stop inbound traffic with fragmented IPv6 packets. The net_ipv6_handle_fragment_hdr path returns without unreferencing the received packet, so its RX memory-slab block is never freed. A few packets exhaust the finite RX pool on IPv6-fragmentation-enabled devices, preventing further packet reception without altering or disclosing data.

The record

CVE
CVE-2026-13351
Published
Jun 25, 2026
Updated
Jun 25, 2026
Vendor
Zephyr Project
Product
Zephyr RTOS
Classifications
CWE-772, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 25, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 25, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=* <=4.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Zephyr Project · Zephyr RTOSversion=* <=4.3

Published CVSS scores

7.5Zephyr ProjectCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-772Missing Release of Resource after Effective Lifetime
T1499.004Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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