CVE-2026-4148ExpressionContext use-after-free in classic engine $lookup and $graphLookup aggregation operators

8.7HighCVSS base score
0.38%Exploitation in 30 daysEPSS · top 68% of all CVEs
NoKnown exploitednot in CISA's KEV catalog
NonePublic exploitsnone known yet

Description

A use-after-free vulnerability can be triggered in sharded clusters by an authenticated user with the read role who issues a specially crafted $lookup or $graphLookup aggregation pipeline.

Timeline

2026
13 Mar 2026
13 Mar 2026
ID reserved
By mongodb
17 Mar 20264 days later
17 Mar 2026· 4 days later
Published
18 Mar 20261 day later
18 Mar 2026· 1 day later
Record updated

Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.

Scores

CVSS scores of CVE-2026-4148, by who scored it
Scored by	CVSS	Score	Vector
mongodbCNA (assigner)	4.0	High8.7	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
mongodbCNA (assigner)	3.1	High8.8	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVDNVD · Analyzed	4.0	High8.7	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

EPSS (exploitation in 30 days): 0.38% · top 68% of all CVEs (12 Nov 2026)
CISA SSVC: Exploitation: none · Automatable: no · Technical impact: total

The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.7.

Affected products

MongoDB Inc · MongoDB Server
- affected 8.2 – < 8.2.6
- affected 8.0 – < 8.0.20
- affected 7.0 – < 7.0.31

References1

https://jira.mongodb.org/browse/SERVER-119319 (opens in a new tab)

Sources

The same CVE in the primary databases and aggregators, to check against.

Badge for a README or a ticket

[![CVE-2026-4148](https://cveledger.app/badge/CVE-2026-4148.svg)](https://cveledger.app/cve/CVE-2026-4148)

Record last updated 18 Mar 2026, 03:55 UTC.