CVE-2026-8718

HIGHPre-NVD 8.48.4—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.4 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.1%, top 98% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Elevated
8.4EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.4Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
8.4
EG Score
8.4(medium)
EG Risk
54(Track)
EG Risk 54/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity84% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
2%
KEV
Not listed

Published

August 10, 2026

Last Modified

August 26, 2026

Advisory Details (2)

Auto-updated Aug 10, 2026
🔬 Proof of concept available. Patch available. Sources: github, github_commit.
github Patch Available🟡 PoC Available

net: sockets: TLS/DTLS: `TLS_DTLS_PEER_CID_VALUE` getter ignores caller buffer size and writes out of bounds · Advisory · zephyrproject-rtos/zephyr · GitHub

https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-p3r6-mx6c-33gq
github_commit

commit aa317825a55a (zephyrproject-rtos/zephyr)

Fix landed in zephyrproject-rtos/zephyr commit aa317825a55a — awaiting tagged release

https://github.com/zephyrproject-rtos/zephyr/commit/aa317825a55a401315e8e17f620c70c02e8f176d

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 11× in last 7d / 39× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-08-30 01:22 UTCEPSS rescore
  2. 2026-08-29 09:53 UTCEG score recompute
  3. 2026-08-28 21:42 UTCEPSS rescore
  4. 2026-08-27 16:40 UTCEG score recompute
  5. 2026-08-27 14:25 UTCEPSS rescore
  6. 2026-08-26 17:27 UTCEG score recompute
  7. 2026-08-26 14:47 UTCEPSS rescore
  8. 2026-08-26 00:36 UTCEG score recompute
  9. 2026-08-25 13:49 UTCEPSS rescore
  10. 2026-08-24 14:39 UTCEG score recompute
  11. 2026-08-24 14:18 UTCEPSS rescore
  12. 2026-08-22 06:01 UTCEG score recompute
  13. 2026-08-21 23:49 UTCEPSS rescore
  14. 2026-08-21 07:22 UTCEG score recompute
  15. 2026-08-20 22:56 UTCEPSS rescore
  16. 2026-08-19 21:25 UTCEG score recompute
  17. 2026-08-19 17:04 UTCEPSS rescore
  18. 2026-08-18 22:31 UTCEG score recompute
  19. 2026-08-18 13:49 UTCEPSS rescore
  20. 2026-08-18 13:49 UTCEPSS rescore
  21. 2026-08-17 23:46 UTCEG score recompute
  22. 2026-08-17 13:47 UTCEPSS rescore
  23. 2026-08-17 01:09 UTCEG score recompute
  24. 2026-08-16 14:56 UTCEPSS rescore
  25. 2026-08-16 14:56 UTCEPSS rescore
Show 14 more
  1. 2026-08-16 02:31 UTCEG score recompute
  2. 2026-08-16 02:15 UTCEPSS rescore
  3. 2026-08-15 03:54 UTCEG score recompute
  4. 2026-08-15 01:31 UTCEPSS rescore
  5. 2026-08-14 05:15 UTCEG score recompute
  6. 2026-08-13 22:00 UTCEPSS rescore
  7. 2026-08-12 19:19 UTCEG score recompute
  8. 2026-08-12 18:56 UTCEG score recompute
  9. 2026-08-12 13:51 UTCEPSS rescore
  10. 2026-08-11 22:10 UTCEG score recompute
  11. 2026-08-11 13:43 UTCEPSS rescore
  12. 2026-08-10 23:31 UTCEG score recompute
  13. 2026-08-10 22:55 UTCEG score recompute
  14. 2026-08-10 22:54 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-8718?
CVE-2026-8718 is a high vulnerability published on August 10, 2026. tlsoptdtlspeerconnectionidvalueget() in subsys/net/lib/sockets/socketstls.c, which handles getsockopt(SOLTLS, TLSDTLSPEERCIDVALUE), passed the caller-supplied optval directly to mbedtlssslgetpeercid() without verifying the buffer was at least MBEDTLSSSLCIDOUTLENMAX (default 32) bytes.…
When was CVE-2026-8718 disclosed?
CVE-2026-8718 was first published in the National Vulnerability Database on August 10, 2026, with the most recent update on August 26, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-8718 actively exploited?
CVE-2026-8718 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 97.7% of all scored CVEs.
What is the CVSS score of CVE-2026-8718?
CVE-2026-8718 has a CVSS v3 base score of 8.4 (NVD).
How do I remediate CVE-2026-8718?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-8718, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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