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Fencer Intel
high 7.6

CVE-2026-18693 json

Out-of-Bounds Read/Write in MongoDB Timeseries Bucket Handling Leads to Denial of Service and Potential Memory Disclosure

published 2mo ago modified 17d ago also BIT-mongodb-2026-18693 , EUVD-2026-56909

cvss
7.6
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 27%
public exploits
0
none known

Summary

An issue in MongoDB Server's handling of timeseries collections could allow an authenticated user with write privileges to cause an internal data structure to become inconsistent through certain document insertions. A subsequent insert into the affected bucket could then result in the server accessing memory outside its intended bounds, potentially causing a server crash (denial of service), exposure of limited memory contents, or memory corruption.

Patch / fix

  • bitnami mongodb 7.0.40, 8.0.29, 8.3.8, 9.0.2
  • MongoDB MongoDB Server 7.0.40, 8.0.29, 8.3.8

Is CVE-2026-18693 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2mo ago

Exploit prediction

0.34% chance of exploitation in the next 30 days, higher than 27% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 4.0 7.2 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N
CNA 3.1 7.6 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:H
CNA 4.0 7.2 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected packages

ecosystem package affected fixed in
bitnami mongodb
>=7.0.0, <7.0.40
>=8.0.0, <8.0.29
>=8.2.0, <8.3.8
>=9.0.0, <9.0.2
7.0.40
8.0.29
8.3.8
9.0.2

Affected products

  • MongoDB MongoDB Server

Classification

Weakness
Technology feeds

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.