MongoDB Server OOB Memory Read via Aggregation Stage
CVE-2026-18688 Published on August 11, 2026
Out-of-Bounds Read in MongoDB Aggregation Framework Leads to Denial of Service and Potential Memory Disclosure
An issue in MongoDB Server's aggregation framework could allow an authenticated user to trigger an out-of-bounds memory read by providing a specially formed numeric parameter in a certain aggregation pipeline stage. This could result in a server crash (denial of service) and may potentially expose a limited amount of memory contents.
Vulnerability Analysis
CVE-2026-18688 is exploitable with network access, and requires small amount of user privileges. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity and availability.
Weakness Type
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.
Products Associated with CVE-2026-18688
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Affected Versions
MongoDB Server:- Version 8.3.0 and below 8.3.8 is affected.
- Version 8.0 and below 8.0.29 is affected.
- Version 7.0 and below 7.0.40 is affected.