Integer overflow in Opener Project
CVE-2026-51536
In OpENer 2.3.0 (commit 76b95cf) when parsing incoming CIP (Common Industrial Protocol) network packets, the length parameter is inconsistently typed across the call stack. Specifically, an upstream length calculated as an int is passed to a downstream function that expects an EipInt16 (a 16-bit signed integer). If a maliciously crafted packet with specific length fields is processed, the length parameter can overflow or be truncated into a negative value. This negative length bypasses subsequent bounds checking (due to signed/unsigned comparison issues) and is ultimately used in memory operations, leading to a Stack Buffer Overflow when reading data in DecodePaddedEPath.
Vulnerability class: Integer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H.
EPSS exploit prediction
EPSS: 0.006 (48.6th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 49th percentile — 48.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.006 · change: +0.001
Affected products
- Opener Project — versions 2.3.0
Weakness classification (CWE)
References
- github.com/EIPStackGroup/OpENer/issues/563 (Exploit, Issue Tracking, Vendor Advisory)
- gist.github.com/MrAlaskan/e160c626a32e03e5d9eddaa732560672 (Third Party Advisory)
Frequently asked questions
- What is CVE-2026-51536?
- CVE-2026-51536 is a critical-severity vulnerability in Opener Project, classified under Integer Overflow or Wraparound. CVSS score: 9.1/10. Published 2026-07-13.
- How severe is CVE-2026-51536?
- Critical severity. CVSS v3 base score is 9.1 out of 10.