IBM i 7.6-7.3 JSSE provider stack overflow via TLS session
CVE-2026-18511 Published on August 13, 2026
IBM i is Affected By Multiple Vulnerabilities in Java Secure Sockets Extension
IBM i 7.6, 7.5, 7.4, and 7.3 could allow a local authenticated attacker to generate a stack-based buffer overflow in the Native IBM i JSSE provider, caused by improper bounds checking during TLS session establishment. A local attacker could overflow a fixed-length buffer and execute arbitrary code on the system or cause the JVM process to crash.
Vulnerability Analysis
CVE-2026-18511 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to be low. considered to have a small impact on confidentiality and integrity and availability.
Weakness Type
What is a Memory Corruption Vulnerability?
The software writes data past the end, or before the beginning, of the intended buffer. Typically, this can result in corruption of data, a crash, or code execution. The software may modify an index or perform pointer arithmetic that references a memory location that is outside of the boundaries of the buffer. A subsequent write operation then produces undefined or unexpected results.
CVE-2026-18511 has been classified to as a Memory Corruption vulnerability or weakness.
Products Associated with CVE-2026-18511
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Affected Versions
IBM i:- Version 7.6 is affected.
- Version 7.5 is affected.
- Version 7.4 is affected.
- Version 7.3 is affected.