Security readout for executives and security teams
Plain-English summary
This flaw let certain legacy plugin-driven POST requests bypass browser cross-origin protections after a 308 redirect. In practical terms, an attacker could abuse an affected Mozilla client to trigger unwanted cross-site actions. The evidence points to older Firefox, Firefox ESR, and Thunderbird releases, not current patched versions.
Executive priority
Prioritize as a legacy remediation and asset hygiene issue. It is not KEV-listed and no active exploitation is cited, but outdated Mozilla clients with old plugin support can expose users to unauthorized cross-site actions. Remediate during endpoint patch and legacy application cleanup.
Technical view
CVE-2019-11712 affects POST requests made by NPAPI plugins, such as Flash. When those requests received HTTP 308 redirects, CORS checks could be bypassed, enabling CSRF-style abuse. Mozilla lists Firefox ESR before 60.8, Firefox before 68, and Thunderbird before 60.8 as affected.
Likely exposure
Likely exposure is concentrated in legacy systems running Firefox < 68, Firefox ESR < 60.8, or Thunderbird < 60.8, especially where NPAPI or Flash-era content was enabled. Current managed browsers should be unaffected if patched, but old kiosks, VDI images, and Linux package baselines need review.
Exploitation context
The provided sources do not show known active exploitation, and CISA KEV status is false. Exploitation would require a vulnerable Mozilla client and conditions involving NPAPI plugin-originated POST traffic with a 308 redirect. Treat this as a legacy client risk rather than broad internet-facing server exposure.
Researcher notes
The public description is specific about the redirect and CORS bypass condition, but no CVSS vector, CWE, exploit evidence, or detailed proof-of-concept is included in the source bundle. Validation should focus on affected product versions and plugin-era configurations rather than speculative exploitability.
Mitigation direction
- Upgrade Firefox to 68 or later where applicable.
- Upgrade Firefox ESR to 60.8 or later where applicable.
- Upgrade Thunderbird to 60.8 or later where applicable.
- Remove or disable legacy NPAPI or Flash dependencies where still present.
- Check Mozilla and OS vendor advisories for supported package versions.
Validation and detection
- Inventory Firefox, Firefox ESR, and Thunderbird versions across managed endpoints.
- Identify systems still permitting NPAPI or Flash-era plugin workflows.
- Confirm Linux distributions applied the relevant 2019 Mozilla security updates.
- Review browser hardening baselines for legacy plugin allowances.
- Prioritize validation on kiosks, VDI images, and unmanaged legacy desktops.
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.
CVE-2019-11712 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
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 and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://www.mozilla.org/security/advisories/mfsa2019-21/CVE reference · x_refsource_MISC
- https://www.mozilla.org/security/advisories/mfsa2019-22/CVE reference · x_refsource_MISC
- https://www.mozilla.org/security/advisories/mfsa2019-23/CVE reference · x_refsource_MISC
- https://bugzilla.mozilla.org/show_bug.cgi?id=1543804CVE reference · x_refsource_MISC
- [debian-lts-announce] 20190802 [SECURITY] [DLA 1869-1] firefox-esr security updateCVE reference · mailing-list, x_refsource_MLIST
- [debian-lts-announce] 20190802 [SECURITY] [DLA 1870-1] thunderbird security updateCVE reference · mailing-list, x_refsource_MLIST
- GLSA-201908-12CVE reference · vendor-advisory, x_refsource_GENTOO
- GLSA-201908-20CVE reference · vendor-advisory, x_refsource_GENTOO
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.