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01 Record

CVE-2026-2776

Sandbox escape due to incorrect boundary conditions in the Telemetry component in External Software

CriticalPUBLISHEDCNA: mozilla
CNA base score10.0 CVSS v3.xCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
View raw JSON

02 Description

Sandbox escape due to incorrect boundary conditions in the Telemetry component in External Software

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.
  • 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
0.56% probability of exploitation activity in the next 30 days.
EPSS percentile
Equal to or higher than the score of 46.5% 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 2026-07-15.
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
2026-02-24 13:33Z8 MO AGO
Last updated
2026-07-15 01:13Z3 MO AGO
Reserved
2026-02-19
Assigning CNA
mozilla
Record state
PUBLISHED
Severity
Critical (CVSS 10.0)
CNA CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Weaknesses
  • CWE-119Improper Restriction of Operations within the Bounds of a Memory BufferClass
Data version
5.2
Document digest
22e66a8b8dbdffa5a12c2760a4d7e9103170c975594277b68362edf09af43b9c

05 Affected products

VendorProductVersionsPlatforms
MozillaFirefoxNot specified—
MozillaThunderbirdNot specified—

06 References

07 Fixed in

AlmaLinux 8

  • firefox
    Fixed in 140.8.0-2.el8_10.alma.1
  • thunderbird
    Fixed in 140.8.0-1.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 140.8.0-2.el9_7.alma.1
  • firefox-x11
    Fixed in 140.8.0-2.el9_7.alma.1
  • thunderbird
    Fixed in 140.8.0-1.el9_7.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 140.8.0-2.el10_1
  • thunderbird
    Fixed in 140.8.0-2.el10_1.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 140.8.0-2.el8_10.alma.1
  • thunderbird
    Fixed in 140.8.0-1.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 140.8.0-2.el9_7.alma.1
  • firefox-x11
    Fixed in 140.8.0-2.el9_7.alma.1
  • thunderbird
    Fixed in 140.8.0-1.el9_7.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 140.8.0-2.el10_1
  • thunderbird
    Fixed in 140.8.0-2.el10_1.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 140.8.0esr-1~deb12u1
  • thunderbird
    Fixed in 1:140.8.0esr-1~deb12u1

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

Debian 13

  • firefox-esr
    Fixed in 140.8.0esr-1~deb13u1
  • thunderbird
    Fixed in 1:140.8.0esr-1~deb13u1

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

Debian 14

  • firefox-esr
    Fixed in 140.8.0esr-1
  • thunderbird
    Fixed in 1:140.8.0esr-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.