CVE-2026-8718
- Source
- https://cve.org/CVERecord?id=CVE-2026-8718
- Import Source
- https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-8718.json
- JSON Data
- https://api.osv.dev/v1/vulns/CVE-2026-8718
- Aliases
-
- GHSA-p3r6-mx6c-33gq
- Published
- 2026-08-10T22:40:26Z
- Modified
- 2026-08-28T14:32:49Z
- Severity
-
- 8.4 (High) CVSS_V3 - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:H CVSS Calculator
- Summary
- Out-of-bounds write in DTLS peer Connection ID getsockopt (`TLS_DTLS_PEER_CID_VALUE`) in Zephyr net sockets/TLS
- Details
-
tls_opt_dtls_peer_connection_id_value_get() in subsys/net/lib/sockets/sockets_tls.c, which handles getsockopt(SOL_TLS, TLS_DTLS_PEER_CID_VALUE), passed the caller-supplied optval directly to mbedtls_ssl_get_peer_cid() without verifying the buffer was at least MBEDTLS_SSL_CID_OUT_LEN_MAX (default 32) bytes. mbedtls_ssl_get_peer_cid() copies the peer-negotiated DTLS Connection ID (length 1..MBEDTLS_SSL_CID_OUT_LEN_MAX) into that buffer without a destination-size parameter, so a caller-supplied optlen smaller than the CID causes a write of up to 31 bytes past the buffer end.
In CONFIG_USERSPACE builds the getsockopt syscall verifier (z_vrfy_zsock_getsockopt) bounce-buffers the user's optval into a kernel allocation of exactly optlen bytes (k_usermode_alloc_from_copy -> z_thread_malloc), so an unprivileged user thread that passes a small optlen on a connected DTLS socket with Connection ID enabled induces a kernel-heap buffer overflow, with the overflowing content being the remote peer's CID.
The defect requires CONFIG_MBEDTLS_SSL_DTLS_CONNECTION_ID, an established DTLS session with a negotiated peer CID, and (for the kernel-crossing case) CONFIG_USERSPACE. Introduced when the TLS_DTLS_CID option was added (v3.5.0).
The fix rejects callers whose optlen is below MBEDTLS_SSL_CID_OUT_LEN_MAX with -EINVAL.
- Database specific
{ "cna_assigner": "zephyr", "cwe_ids": [ "CWE-787" ], "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/8xxx/CVE-2026-8718.json" }- References
-
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/8xxx/CVE-2026-8718.json
- https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-p3r6-mx6c-33gq
- https://nvd.nist.gov/vuln/detail/CVE-2026-8718
- https://github.com/zephyrproject-rtos/zephyr/commit/aa317825a55a401315e8e17f620c70c02e8f176d
- https://github.com/zephyrproject-rtos/zephyr
Affected packages
Git / github.com/zephyrproject-rtos/zephyr
Affected versions
v3.*
v4.*
zephyr-v3.*
Database specific
source
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-8718.json"
vanir_signatures
[
{
"deprecated": false,
"digest": {
"line_hashes": [
"213985566104757576475726432279289364420",
"280578132596159187513546376525002284885",
"113304156645486097580760699769014025419"
],
"threshold": 0.9
},
"id": "CVE-2026-8718-7ea00dda",
"signature_type": "Line",
"signature_version": "v1",
"source": "https://github.com/zephyrproject-rtos/zephyr/commit/aa317825a55a401315e8e17f620c70c02e8f176d",
"target": {
"file": "subsys/net/lib/sockets/sockets_tls.c"
}
},
{
"deprecated": false,
"digest": {
"function_hash": "125992766346141062699934189776774684232",
"length": 475
},
"id": "CVE-2026-8718-a7e82782",
"signature_type": "Function",
"signature_version": "v1",
"source": "https://github.com/zephyrproject-rtos/zephyr/commit/aa317825a55a401315e8e17f620c70c02e8f176d",
"target": {
"file": "subsys/net/lib/sockets/sockets_tls.c",
"function": "tls_opt_dtls_peer_connection_id_value_get"
}
}
]
vanir_signatures_modified
"2026-08-28T14:32:49Z"