Unauthenticated memory corruption via unbounded MQTT varint decoding
Published Jan 27, 2026 · Updated Jan 27, 2026
Heap-based buffer overflow in ttttupup wxhelper through 3.9.10.19-v1 allows remote attackers to corrupt memory via crafted MQTT 5 PUBLISH packets. The bundled Mongoose decode_variable_length routine reads as many as four bytes without checking the remaining packet length. The parser must receive MQTT 5 traffic; demonstrated exploitation terminates the hosting process, while code execution is not publicly demonstrated.
Summary
What happened
Heap-based buffer overflow in ttttupup wxhelper through 3.9.10.19-v1 allows remote attackers to corrupt memory via crafted MQTT 5 PUBLISH packets. The bundled Mongoose decode_variable_length routine reads as many as four bytes without checking the remaining packet length. The parser must receive MQTT 5 traffic; demonstrated exploitation terminates the hosting process, while code execution is not publicly demonstrated.
The record
- CVE
- CVE-2026-24822
- Published
- Jan 27, 2026
- Updated
- Jan 27, 2026
- Vendor
- ttttupup
- Product
- wxhelper
- Classifications
- CWE-787, CWE-122, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jan 27, 2026CVE publishedPublication date reported by the CVE source.
- Jan 27, 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.
- Affected versionversion=0 <=3.9.10.19-v1
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
Weakness, pattern, technique
Public exploit references
- Mongoose MQTT PUBLISH crash proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
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