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01 Record

CVE-2020-12391

Documents formed using data: URLs in an OBJECT element failed to inherit the CSP of the creating context. This allowed the execution of scripts that should have been blocked, albeit with a unique

UnratedPUBLISHEDCNA: mozilla
CNA base scoreUnratedNo CNA CVSS vector

02 Description

Documents formed using data: URLs in an OBJECT element failed to inherit the CSP of the creating context. This allowed the execution of scripts that should have been blocked, albeit with a unique

03 Exploitation and scoring

Exploitation
Not assessed. CISA has not published an exploitation assessment for this record, and it is not in the KEV catalog. That is an absence of assessment, not a finding of no risk.
SSVC decision
Not assessed by CISA
EPSS probability
1.46% probability of exploitation activity in the next 30 days.
EPSS percentile
Equal to or higher than the score of 73.3% of scored records. A rank, not a probability.
NVD base score
7.5 (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:U/C:N/I:H/A:N
NVD analysis status
Modified. NVD last modified this record on 2026-06-17.
Red Hat severity
Moderate. 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.

04 Metadata

Published
2020-05-26 17:02Z6 YR AGO
Last updated
2024-08-04 11:56Z2 YR AGO
Reserved
2020-04-28
Assigning CNA
mozilla
Record state
PUBLISHED
Severity
Not rated by the issuing CNA
CNA CVSS vector
Not published by the issuing CNA
Weaknesses
  • CWE-863Incorrect AuthorizationClass
  • CWE-358Improperly Implemented Security Check for StandardBase
Data version
5.1
Document digest
76f07ad4601cb98cd6b10322aed2e0efd2a71c2f357f746bd3e503dc9637929e

05 Affected products

VendorProductVersionsPlatforms
MozillaFirefox< 76—

06 References

07 Fixed in

Arch Linux

  • firefox
    Fixed in 76.0-1

Source: Arch Linux Security Tracker, the Arch Linux security team. Reformatted by exploit.cc.

Ubuntu 16.04 LTS

  • firefox
    Fixed in 76.0+build2-0ubuntu0.16.04.1

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 18.04 LTS

  • firefox
    Fixed in 76.0+build2-0ubuntu0.18.04.1
  • mozjs38
    No fix yet
  • mozjs52
    No fix yet

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 20.04 LTS

  • firefox
    Fixed in 76.0+build2-0ubuntu0.20.04.1
  • mozjs52
    No fix yet
  • mozjs68
    No fix yet

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

A release or ecosystem missing from this list has no record here. It may be unaffected or not covered by the source. Source notices and licences.