Pre-auth Crash in Eclipse Open9J JITServer via 32-Byte TCP Message
CVE-2026-6918 Published on May 5, 2026
In Eclipse Open9J versions 0.21 to 0.58, a pre-authentication remote attacker can crash JITServer by sending a 32-byte crafted TCP message.
Vulnerability Analysis
CVE-2026-6918 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. An automatable proof of concept (POC) exploit exists. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.
Weakness Types
Out-of-bounds Read
The software reads data past the end, or before the beginning, of the intended buffer. Typically, this can allow attackers to read sensitive information from other memory locations or cause a crash. A crash can occur when the code reads a variable amount of data and assumes that a sentinel exists to stop the read operation, such as a NUL in a string. The expected sentinel might not be located in the out-of-bounds memory, causing excessive data to be read, leading to a segmentation fault or a buffer overflow. 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 read operation then produces undefined or unexpected results.
Improper Validation of Syntactic Correctness of Input
The product receives input that is expected to be well-formed - i.e., to comply with a certain syntax - but it does not validate or incorrectly validates that the input complies with the syntax.
Products Associated with CVE-2026-6918
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Affected Versions
Eclipse Foundation Eclipse OpenJ9:- Version 0.21 and below 0.59 is affected.
- Version 1:21.0.11.0.10-2.el10_1 and below * is unaffected.
- Version 1:21.0.11.0.10-1.el10_0 and below * is unaffected.
- Version 1:21.0.11.0.10-2.el10_1 and below * is unaffected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.