CVE-2026-0879: Sandbox escape due to incorrect boundary conditions in the Graphics component

Published Jan 13, 2026
·
Updated

Sandbox escape due to incorrect boundary conditions in the Graphics component. This vulnerability was fixed in Firefox 147, Firefox ESR 115.32, Firefox ESR 140.7, Thunderbird 147, and Thunderbird 140.7.

Other sources

Sandbox escape due to incorrect boundary conditions in the Graphics component. This vulnerability affects Firefox < 147, Firefox ESR < 115.32, and Firefox ESR < 140.7.

— Red Hat

Affected Software

23 affected componentsFixes available
Mozilla Firefox ESR<115.32
115.32
Mozilla Thunderbird<147
147
Mozilla Firefox<115.32.0
Mozilla Firefox<147.0
Mozilla Firefox>=128.0<140.7.0
Mozilla Thunderbird<140.7.0
Mozilla Thunderbird<147.0
ubuntu/mozjs52*
ubuntu/mozjs38*
ubuntu/mozjs68*
ubuntu/mozjs52*
ubuntu/mozjs102*
ubuntu/mozjs78*
ubuntu/mozjs91*
ubuntu/thunderbird<1:140.7.1+build1-0ubuntu0.22.04.1
1:140.7.1+build1-0ubuntu0.22.04.1
ubuntu/mozjs102*
ubuntu/mozjs115*
Mozilla Firefox<147
147
Mozilla Firefox ESR<140.7
140.7
Mozilla Thunderbird<140.7
140.7
debian/firefox
160.0-1
debian/firefox-esr
140.12.0esr-1~deb12u1153.7.0esr-1~deb12u1140.15.0esr-1~deb13u1153.6.0esr-1~deb13u1153.5.1esr-1153.7.0esr-1
debian/thunderbird
1:140.12.0esr-1~deb12u11:153.6.0esr-1~deb12u21:140.12.0esr-1~deb13u11:153.6.0esr-1~deb13u11:153.5.0esr-11:153.7.0esr-1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 115.32
  2. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 147
  3. Upgrade

    Upgrade ubuntu/thunderbird to a version that resolves this vulnerability.

    Fixed in 1:140.7.1+build1-0ubuntu0.22.04.1
  4. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 140.7
  5. Upgrade

    Upgrade debian/firefox to a version that resolves this vulnerability.

    Fixed in 160.0-1
  6. Upgrade

    Upgrade debian/firefox-esr to a version that resolves this vulnerability.

    Fixed in 140.12.0esr-1~deb12u1Fixed in 153.7.0esr-1~deb12u1Fixed in 140.15.0esr-1~deb13u1Fixed in 153.6.0esr-1~deb13u1Fixed in 153.5.1esr-1Fixed in 153.7.0esr-1
  7. Upgrade

    Upgrade debian/thunderbird to a version that resolves this vulnerability.

    Fixed in 1:140.12.0esr-1~deb12u1Fixed in 1:153.6.0esr-1~deb12u2Fixed in 1:140.12.0esr-1~deb13u1Fixed in 1:153.6.0esr-1~deb13u1Fixed in 1:153.5.0esr-1Fixed in 1:153.7.0esr-1
  8. Upgrade

    Upgrade Firefox to a version that resolves this vulnerability.

    Fixed in 147
  9. Upgrade

    Upgrade Firefox ESR to a version that resolves this vulnerability.

    Fixed in 115.32
  10. Upgrade

    Upgrade Firefox ESR to a version that resolves this vulnerability.

    Fixed in 140.7
  11. Upgrade

    Upgrade Thunderbird to a version that resolves this vulnerability.

    Fixed in 147
  12. Upgrade

    Upgrade Thunderbird to a version that resolves this vulnerability.

    Fixed in 140.7

Event History

Jan 13, 2026
CVE Published
via Mozilla·12:00 AM
Data Sourced
via Mozilla·12:00 AM
DescriptionSeverityAffected Software
Data Sourced
via Ubuntu·12:00 AM
RemedyDescriptionSeverityAffected Software
CVE Published
via MITRE·01:30 PM
Data Sourced
via MITRE·01:30 PM
Description
Data Sourced
via Red Hat·02:02 PM
DescriptionSeverityAffected Software
Data Sourced
via OSV·02:16 PM
DescriptionSeverityAffected Software
Data Sourced
via NVD·02:16 PM
DescriptionSeverityWeaknessAffected Software

Parent advisories

This vulnerability appears in the following advisories.

Peer vulnerabilities

Found alongside the following vulnerabilities.

Frequently Asked Questions

1

What is the severity of CVE-2026-0879?

CVE-2026-0879 is classified as a critical vulnerability due to its potential to allow unauthorized access and impact user security.

2

How do I fix CVE-2026-0879?

To fix CVE-2026-0879, upgrade to Mozilla Firefox version 147, Firefox ESR version 115.32, or version 140.7.

3

What versions of Firefox are affected by CVE-2026-0879?

CVE-2026-0879 affects Firefox versions earlier than 147, and Firefox ESR versions earlier than 115.32 and 140.7.

4

What type of vulnerability is CVE-2026-0879?

CVE-2026-0879 is a sandbox escape vulnerability resulting from incorrect boundary conditions in the Graphics component.

5

Can CVE-2026-0879 be exploited remotely?

Yes, CVE-2026-0879 can potentially be exploited remotely, allowing an attacker to escape the sandbox and execute arbitrary code.

Company

Resources

Contact

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