CVE-2021-4140

Exploitation

Public exploit code exists. CISA's assessment records a public proof of concept. That is not a report of exploitation in the wild.

SSVC decision

• ExploitationpocPublic proof-of-concept exploit code exists. Not a report of exploitation in the wild.
• AutomatableyesAn attacker can reliably automate reconnaissance through exploitation, so this scales.
• Technical ImpacttotalSuccessful exploitation gives total control of the vulnerable component.

CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.

EPSS probability

1.34% probability of exploitation activity in the next 30 days.

EPSS percentile

Ranks above 69.3% of scored records. A rank, not a probability.

NVD base score

10.0 (CVSS v3.x), scored by the NVD independently of the CNA.

NVD CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

NVD analysis status

Modified. NVD last modified this record on 2026-06-17.

Red Hat severity

Important. Red Hat's rating for its own products, not a CVSS rating.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

Published

2022-12-22 00:00Z3 YR AGO

Last updated

2025-04-16 15:55Z1 YR AGO

Reserved

2021-12-20

Assigning CNA

mozilla

Record state

PUBLISHED

Severity

Critical (CVSS 9.8)

CNA CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Weaknesses

• CWE-91XML Injection (aka Blind XPath Injection)Base
• CWE-1021Improper Restriction of Rendered UI Layers or FramesBase

Data version

5.1

Document digest

ee3f0791cd0cbb8cf97b7918dbf24481e1df86a5a17ccdf8a8cfd8c9eb2aaa56

• www.mozilla.orghttps://www.mozilla.org/security/advisories/mfsa2022-01/
• www.mozilla.orghttps://www.mozilla.org/security/advisories/mfsa2022-02/
• www.mozilla.orghttps://www.mozilla.org/security/advisories/mfsa2022-03/
• bugzilla.mozilla.orghttps://bugzilla.mozilla.org/show_bug.cgi?id=1746720