Security readout for executives and security teams
Plain-English summary
This is a critical Firefox sandbox escape. If an attacker already compromises a browser child process, the flaw could let them cross into privileged browser code and execute arbitrary code. The source bundle identifies Firefox versions before 70 as affected.
Executive priority
Treat as urgent only where old Firefox remains deployed. For fully patched fleets, the business risk is mainly assurance: prove no pre-70 Firefox versions exist.
Technical view
Mozilla describes a compromised child process injecting XBL Bindings into privileged CSS rules, leading to arbitrary code execution and sandbox escape. The CVSS 3.1 score is 10.0, with network attack vector and no privileges or user interaction listed in the CVE metadata.
Likely exposure
Exposure is limited to Mozilla Firefox installations older than version 70. The most likely remaining risk is unmanaged, legacy, kiosk, lab, or long-lived workstation images that missed browser updates.
Exploitation context
The provided sources do not show CISA KEV listing or active exploitation. The vulnerability is still high impact because it breaks a browser sandbox boundary after child-process compromise, but exploitation status is not established by the bundle.
Researcher notes
Key evidence is concise: affected product is Firefox below 70; impact is arbitrary code execution and sandbox escape through XBL binding injection into privileged CSS rules. The bundle does not provide exploit proof, affected platform detail, or separate workaround guidance.
Mitigation direction
- Upgrade Firefox to version 70 or later using Mozilla guidance.
- Remove unsupported or unmanaged Firefox installations from endpoints.
- Prioritize legacy workstations, kiosks, and shared machines for browser update verification.
- Check vendor advisory details before relying on compensating controls.
Validation and detection
- Inventory installed Firefox versions across managed and unmanaged endpoints.
- Confirm no Firefox installations report versions earlier than 70.
- Review vulnerability scanner findings for CVE-2019-25136 or Firefox below 70.
- Validate endpoint management policies enforce current Firefox updates.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
Execution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupPrivilege behavior lookup
The CVE wording references privilege impact, so privilege escalation and authorization behavior review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2019-25136 mapping review
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Open ATT&CK lookup- Severity
- Critical
- CVSS
- 10 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H3.96Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
10CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://bugzilla.mozilla.org/show_bug.cgi?id=1530709CVE reference
- https://www.mozilla.org/security/advisories/mfsa2019-34/CVE reference
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.