Out-of-Bounds Read in NanoMQ (CVE-2026-35217)
Summary
Vulnerability in NanoMQ (CVE-2026-35217). Risk of unauthorized operations or information disclosure. Exploitable via SUBSCRIBE.
Original description
The description as published by the source.
NanoMQ contains a protocol-semantics flaw in its MQTT v5 SUBSCRIBE handling: if a subscription entry is missing the final 1-byte Subscription Options field, the broker may still accept the malformed packet and install the subscription into internal broker state. Under a specific packet-length construction, the same parser flaw also causes a 1-byte out-of-bounds read that crosses the real heap allocation boundary and is detected by ASAN as a heap-buffer-overflow.
If the consumed byte happens to look acceptable, NanoMQ may continue and append the malformed subscription entry into its internal subinfol state. In that case, a SUBSCRIBE packet that should be rejected by MQTT rules is instead treated as a successful subscription. Whether ASAN reports the bug does not depend on MQTT's logical remain boundary; it depends on whether the read crosses the real heap allocation boundary of the underlying message buffer. In other words, these are not two unrelated issues. They are two manifestations of the same parsing defect: by default, it appears as a semantic vulnerability, and under suitable input conditions, it also becomes a verifiable out-of-bounds read vulnerability.
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-35217 has been found in NanoMQ.
Attackers can target a specific entry point like SUBSCRIBE over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 6.5/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "NanoMQ CVE-2026-35217" on the vendor's site.
CVE-2026-35217 (NanoMQ) — CWE-125 / CVSS v3 6.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: SUBSCRIBE / subinfol / remain
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Out-of-bounds read (CWE-125) exists in NanoMQ. Attackers reach the vulnerable code path via SUBSCRIBE without authentication.
Check the vendor advisory for the affected versions of NanoMQ. Attack surface: SUBSCRIBE / subinfol / remain.
Severity: Medium (CVSS 6.5/10). Risk of unauthorized operations or information disclosure.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'NanoMQ' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'NanoMQ' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
NanoMQを grep し、稼働しているサービス・バージョンを把握する。 -
2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
References
- advisory github.com
- advisory github.com
- advisory nvd.nist.gov