CVE-2026-73863
NanoMQ: Heap-Buffer-Overflow in `nmq_subinfo_decode()` During MQTT v5 SUBSCRIBE Parsing
- Published
- Updated
- Reserved
- Assigned by
- GitHub_M
Description
NanoMQ is an MQTT broker. Prior to 0.24.14, NanoMQ's broker-side MQTT v5 nmq_subinfo_decode() function in nng/src/sp/protocol/mqtt/mqtt_parser.c reuses len_of_varint from the outer Properties Length while parsing each SUBSCRIPTION_IDENTIFIER. A remote client can send a SUBSCRIBE packet with a multi-byte Properties Length and repeated subscription identifiers, causing get_var_integer() to begin at an incorrect offset and read beyond the heap message buffer. The flaw is reachable through the broker receive path and can crash the broker, while the separately reported topic-option off-by-one occurs later and is not this vulnerability. This issue is fixed in version 0.24.14.
Public exploit
A reference of the record is tagged as an exploit or proof of concept: anyone can try it against an unpatched system. CISA's SSVC rates its exploitation: a proof of concept is public.
- https://github.com/nanomq/nanomq/security/advisories/GHSA-pf97-vm7h-q84m (opens in a new tab)x_refsource_CONFIRMexploit
Timeline
ID reserved
By GitHub_M
- 36 days later
· 36 days later
Published
- 6 days later
· 6 days later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 4.0 | High7.0 | CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:H |
| NVDNVD · Deferred | 4.0 | High7.0 | CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
- EPSS (exploitation in 30 days)
- 0.35% · top 71% of all CVEs (7 Nov 2026)
- CISA SSVC
- Exploitation: poc · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.0.
Weakness
Affected products
References (4)
- https://github.com/nanomq/nanomq/security/advisories/GHSA-pf97-vm7h-q84m (opens in a new tab)x_refsource_CONFIRMexploit
- https://github.com/nanomq/NanoNNG/pull/1518 (opens in a new tab)x_refsource_MISC
- https://github.com/nanomq/NanoNNG/commit/f888fe39d6691b253ff9aee598ce58bbe449ab6f (opens in a new tab)x_refsource_MISC
- https://github.com/nanomq/nanomq/releases/tag/0.24.14 (opens in a new tab)x_refsource_MISC
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-73863)Record last updated .