Home/CVE/Sandbox escape due to incorrect boundary conditions in the DOM: Core & HTML component. This vulnerability was fixed in F
CVE

CVE-2026-2778

Sandbox escape due to incorrect boundary conditions in the DOM: Core & HTML component. This vulnerability was fixed in F

Sandbox escape due to incorrect boundary conditions in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.

CRITICAL · CVSS 10 EPSS 0.00029
Schedule remediation
  • SSVC automatable: yes - attacks can be scripted at scale
  • CVSS base score ≥ 7.0
Sigma rules1 YARA rules0
⬡

Weakness Classification

CWE-119Improper Restriction of Operations within the Bounds of a Memory Buffer
▤

Affected Products & Versions

5
mozilla firefox< 115.33.0
mozilla firefox< 148.0
mozilla firefox>= 128.0 and < 140.8.0
mozilla thunderbird< 140.8.0
mozilla thunderbird< 148.0
◈

Sigma Hunt Rules

1
Exact rules name this CVE ID. Product rules name an affected product in their title. Related rules cover techniques used by actors who exploited this CVE. Showing the most relevant matches; the complete related set is on the full drill-down.
producthighSQLite Firefox Profile Data DB Access
▣

Scoring & Timeline

10
CRITICAL · CVSS v3.1 · security@mozilla.org
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD24 Feb 2026 · 02:16 PM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
SSVC triage · cisa-vulnrichment
Exploitation
none
Automatable
yes
Technical impact
total
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
⚑

Vendor Advisories

30
suse-csafopenSUSE-SU-2026:20391-1
suse-csafopenSUSE-SU-2026:20365-1
suse-csafSUSE-SU-2026:0880-1
suse-csafSUSE-SU-2026:0871-1
suse-csafSUSE-SU-2026:0812-1
🔗

References & Sources

6
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://bugzilla.mozilla.org/show_bug.cgi?id=2016358Issue TrackingPermissions Required
https://www.mozilla.org/security/advisories/mfsa2026-13/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-14/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-15/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-16/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-17/Vendor Advisory
Intelligence Graph · click any node to traverse
CVETechnique ActorTool Family
drag to reposition · click any node to traverse · button top-right enlarges
External lookups - second-class, for what we don’t hold ourselves
NVDCVE.orgCISAVulnersExploit-DBGitHub PoCVulnCheck KEVGreyNoise
Vulnerabilities
CISA KEV catalog
CWE weaknesses
CAPEC attack patterns
Package vulnerabilities
Threat intelligence
Threat actors
Tools & malware
ATT&CK techniques
IOCs
Detection & defense
Sigma rules
YARA rules
Atomic Red Team tests
D3FEND countermeasures
Compliance
NIST 800-53
ISO 27001:2022
SOC 2 TSC
PCI-DSS v4.0
CIS Controls v8.1
About
All capabilities
Live statistics
Data sources
Privacy policy
Terms of service
threatengine.sh  ·  Open-source threat intelligence platform  ·  100+ authoritative sources  ·  Every fact traces to its origin