8.6

CVE-2026-81522: mongodb c_driver Improper Encoding or Escaping of Output

CVSS: 8.6v4.0HighAnalyzed
AliasesDEBIAN-CVE-2026-81522UBUNTU-CVE-2026-81522
Published 27-08-2026Last modified 29-08-2026
Open JSON

Vulnerability summary

CVE-2026-81522 is a high (CVSS 8.6) Improper Encoding or Escaping of Output vulnerability in mongodb c_driver. EPSS estimates a 0.46% chance of exploitation in the next 30 days, higher than 38.7% of scored vulnerabilities.

Overall risk
34/100
0100
Medium · default modelHow is this calculated?
CVSS score
8.6/10
010
High · v4.0 (CVE.org)
EPSS score
0.46%
0%100%
Low · +0.20 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 27-08-2026
    PublishedVulnerability first disclosed.
  2. 29-08-2026
    Last modifiedVulnerability information updated.

Description

A weakness in the MongoDB C++ Driver's handling of caller-supplied namespace identifiers allows special characters embedded in those identifiers. An application that builds a namespace identifier from untrusted input without validating it may therefore have its operation directed at a different target than intended. This can result in limited unauthorized read and write access to data belonging to another logical tenant of the affected application.

CVSS metrics

7 scores · 4 sources · 2 versions

EPSS trend

Probability

0.46%

Chance of exploitation in the next 30 days

Percentile

39%

Versus all other CVEs

30-day change

+0.20 pp

From 0.27% on 20-09-2026

20-09-202620-10-2026
EPSS score
0.46%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Debian1 product
  • mongo-cxx-driver< 4.5.1-1
Mongodb1 product
  • c_driver≥ 3.0.0, < 4.5.1 | ≥ 3.0.0, < 4.5.2
Ubuntu1 product
  • mongo-cxx-driverAll versions (No fix recorded)

3 vendors · 3 products

References

5 links