CVE-2026-88351 json
An integer overflow vulnerability exists in the MPack Node API in MPack 1.1.1 on 32-bit platforms.
published 2026-09-24 46 d ago modified 2026-09-25 44 d ago also EUVD-2026-86022
- cvss
- 9.8
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.4%
- EPSS 0.4% chance of exploitation in 30 days, percentile 33%
- public exploits
- 0
- none known
Summary
An integer overflow vulnerability exists in the MPack Node API in MPack 1.1.1 on 32-bit platforms. When parsing a specially crafted MessagePack array32 or map32 object with an excessively large element count, the page allocation size calculation in mpack_tree_parse_children() can overflow size_t and produce an undersized allocation. Subsequent parsing writes mpack_node_data_t records beyond the allocated heap buffer, resulting in heap-buffer-overflow, memory corruption, and denial of service.
Patch / fix
CISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- yes
- Technical impact
- total
- Assessed
- 44 d ago
Exploit prediction
0.39% chance of exploitation in the next 30 days, higher than 33% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- github.com https://github.com/ludocode/mpack/issues/123 referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CISA ADP | 3.1 | 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| CNA | 3.1 | 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
Classification
- Weakness
-
- CWE-190 Integer Overflow or Wraparound
References
Sources
- CVE List CVE-2026-88351
- NVD CVE-2026-88351
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