Post-authentication use-after-free in MongoDB Server time-series bucket validation

published 2026-11-10 yesterday modified 2026-11-10 yesterday also EUVD-2026-122840

cvss: 8.8; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.6%; EPSS 0.6% chance of exploitation in 30 days, percentile 49%
public exploits: 0; none known

A use-after-free in the time-series collection component of MongoDB Server can occur when the server validates a time-series bucket document during a write. The condition can be caused by an authenticated user with privileges to write bucket documents directly, and may result in the server terminating unexpectedly or, under certain conditions, arbitrary code execution in the context of the server process.

Patch / fix

fixed in 1

MongoDB MongoDB Server 7.0.48, 8.0.37, 8.3.16, 9.0.7

Is CVE-2026-120824 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

Exploit prediction

0.62% chance of exploitation in the next 30 days, higher than 49% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by	version	score	vector
CNA	4.0	8.7	CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CNA	3.1	8.8	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CNA	4.0	8.7	CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/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 products

MongoDB MongoDB Server

Classification

Weakness

CWE-416 Use After Free

Technology feeds

MongoDB rss critical rss

References

jira.mongodb.org /browse/SERVER-136505

Sources

CVE List CVE-2026-120824
NVD CVE-2026-120824

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.