CVE-2021-3319Network attack vector

Firmware crash via unchecked absent frame addresses

Published Oct 5, 2021 · Updated Sep 16, 2024

NULL pointer dereference in Zephyr RTOS after 2.4.0 and before 2.5.0 allows remote attackers to crash firmware via malformed IEEE 802.15.4 frames. ieee802154_validate_frame accepts failed address validation, and set_pkt_ll_addr converts the resulting NULL address into pointer 2 before sys_mem_swap writes to low memory. Unauthenticated radio reachability to an IEEE 802.15.4-enabled device is required; most systems crash, while certain memory layouts can execute attacker-controlled code after reset.

CVSS severity6.5
Medium
EPSS probability0.88%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in Zephyr RTOS after 2.4.0 and before 2.5.0 allows remote attackers to crash firmware via malformed IEEE 802.15.4 frames. ieee802154_validate_frame accepts failed address validation, and set_pkt_ll_addr converts the resulting NULL address into pointer 2 before sys_mem_swap writes to low memory. Unauthenticated radio reachability to an IEEE 802.15.4-enabled device is required; most systems crash, while certain memory layouts can execute attacker-controlled code after reset.

The record

CVE
CVE-2021-3319
Published
Oct 5, 2021
Updated
Sep 16, 2024
Vendor
Zephyr Project
Product
Zephyr RTOS
Classifications
CWE-588, CWE-476, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 5, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 2024Record 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=> v2.4.0 <unspecified

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Zephyr Project · Zephyr RTOSversion=> v2.4.0 <unspecified

Published CVSS scores

6.5Zephyr ProjectCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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 exploitUnconfirmed

Weakness, pattern, technique

CWE-588Attempt to Access Child of a Non-structure Pointer
CWE-476NULL Pointer Dereference
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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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