CVE-2026-8718Public exploit

Kernel memory corruption via undersized DTLS CID buffer

Published Aug 10, 2026 · Updated Aug 10, 2026

Out-of-bounds write in Zephyr RTOS 3.5.0 through 4.4.0 allows local users to corrupt kernel memory via an undersized DTLS CID buffer. tls_opt_dtls_peer_connection_id_value_get() passes the caller-sized optval to mbedtls_ssl_get_peer_cid(), which copies up to 32 peer CID bytes without a destination-size parameter. Exploitation requires a negotiated DTLS peer CID and CONFIG_MBEDTLS_SSL_DTLS_CONNECTION_ID; crossing into the kernel heap also requires CONFIG_USERSPACE and a low-privileged user thread.

CVSS severity8.4
High
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds write in Zephyr RTOS 3.5.0 through 4.4.0 allows local users to corrupt kernel memory via an undersized DTLS CID buffer. tls_opt_dtls_peer_connection_id_value_get() passes the caller-sized optval to mbedtls_ssl_get_peer_cid(), which copies up to 32 peer CID bytes without a destination-size parameter. Exploitation requires a negotiated DTLS peer CID and CONFIG_MBEDTLS_SSL_DTLS_CONNECTION_ID; crossing into the kernel heap also requires CONFIG_USERSPACE and a low-privileged user thread.

The record

CVE
CVE-2026-8718
Published
Aug 10, 2026
Updated
Aug 10, 2026
Vendor
Zephyr Project
Product
Zephyr RTOS
Classifications
CWE-787, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 10, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 10, 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=3.5.0 <4.4.1

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Zephyr Project · Zephyr RTOSversion=3.5.0 <4.4.1

Published CVSS scores

8.4Zephyr ProjectCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/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.

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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)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1068Exploitation for Privilege Escalation

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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