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01 Record

CVE-2026-84124

Use-after-free in the DOM: Core & HTML component

MediumPUBLISHEDCNA: mozilla
CNA base score5.4 CVSS v3.xCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
View raw JSON

02 Description

Use-after-free in the DOM: Core & HTML component

03 Exploitation and scoring

Exploitation
Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.
SSVC decision
  • ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
  • AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
  • Technical ImpactpartialSuccessful exploitation gives limited 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
0.17% probability of exploitation activity in the next 30 days.
EPSS percentile
Equal to or higher than the score of 6.3% of scored records. A rank, not a probability.
NVD base score
5.4 (CVSS v3.x), scored by the NVD independently of the CNA.
NVD CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
NVD analysis status
Analyzed. NVD last modified this record on 2026-09-02.
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.

04 Metadata

Published
2026-09-01 12:18Z1 MO AGO
Last updated
2026-09-01 21:44Z1 MO AGO
Reserved
2026-09-01
Assigning CNA
mozilla
Record state
PUBLISHED
Severity
Medium (CVSS 5.4)
CNA CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
Weaknesses
Data version
5.2
Document digest
62892ddfd1288a739b63ad69175f4c95150b8edf178e01d7b954c31e9f02077e

05 Affected products

VendorProductVersionsPlatforms
MozillaFirefoxNot specified—
MozillaThunderbirdNot specified—

06 References

07 Fixed in

AlmaLinux 8

  • firefox
    Fixed in 140.15.0-1.el8_10.alma.1
  • thunderbird
    Fixed in 140.16.0-1.el8_10.alma.1

Source: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.

AlmaLinux 9

  • firefox
    Fixed in 140.15.0-1.el9_8.alma.1
  • firefox-x11
    Fixed in 140.15.0-1.el9_8.alma.1
  • thunderbird
    Fixed in 140.16.0-1.el9_8.alma.1

Source: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.

AlmaLinux 10

  • firefox
    Fixed in 140.15.0-1.el10_2
  • thunderbird
    Fixed in 140.16.0-1.el10_2.alma.1

Source: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.

CloudLinux 8

  • firefox
    Fixed in 140.15.0-1.el8_10.alma.1
  • thunderbird
    Fixed in 140.16.0-1.el8_10.alma.1

Derived from AlmaLinux 8. Partial coverage: only packages taken from AlmaLinux 8 are listed.

Source: CloudLinux errata, CloudLinux Inc. Derived from: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.

CloudLinux 9

  • firefox
    Fixed in 140.15.0-1.el9_8.alma.1
  • firefox-x11
    Fixed in 140.15.0-1.el9_8.alma.1
  • thunderbird
    Fixed in 140.16.0-1.el9_8.alma.1

Derived from AlmaLinux 9. Partial coverage: only packages taken from AlmaLinux 9 are listed.

Source: CloudLinux errata, CloudLinux Inc. Derived from: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.

CloudLinux 10

  • firefox
    Fixed in 140.15.0-1.el10_2
  • thunderbird
    Fixed in 140.16.0-1.el10_2.alma.1

Derived from AlmaLinux 10. Partial coverage: only packages taken from AlmaLinux 10 are listed.

Source: CloudLinux errata, CloudLinux Inc. Derived from: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.

Debian 12

  • firefox-esr
    Fixed in 140.15.0esr-1~deb12u1
  • thunderbird
    Fixed in 1:140.15.0esr-1~deb12u1

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Debian 13

  • firefox-esr
    Fixed in 140.15.0esr-1~deb13u1
  • thunderbird
    Fixed in 1:140.15.0esr-1~deb13u1

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Debian 14

  • firefox-esr
    Fixed in 140.15.0esr-1
  • thunderbird
    Fixed in 1:153.2.0esr-1

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 18.04 LTS

  • 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

  • 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.

Ubuntu 22.04 LTS

  • mozjs102
    No fix yet
  • mozjs78
    No fix yet
  • mozjs91
    No fix yet
  • thunderbird
    No fix yet

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

Ubuntu 24.04 LTS

  • mozjs102
    No fix yet
  • mozjs115
    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.