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CVE Record

CVE-2026-12289: Privilege escalation in the Graphics: WebRender component

Privilege escalation in the Graphics: WebRender component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Firefox ESR 115.37, Thunderbird 152, and Thunderbird 140.12.

HighCVSS 8.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2026-12289 is a high-severity Mozilla flaw in the WebRender graphics component. A user may need to interact with malicious content, but successful exploitation could compromise confidentiality, integrity, and availability. Mozilla states it is fixed in current Firefox, Firefox ESR, and Thunderbird releases named in the advisories.

Executive priority

Treat as high priority for endpoint patching. It affects common browser and mail clients, has high potential impact, and has vendor fixes available, but the provided sources do not establish active exploitation.

Technical view

The CVE describes privilege escalation in Graphics: WebRender, mapped to CWE-266 and CWE-269. CVSS 3.1 is 8.8: network reachable, low attack complexity, no privileges required, user interaction required, unchanged scope, and high impact across CIA.

Likely exposure

Exposure is most likely on endpoints running Firefox, Firefox ESR, or Thunderbird below Mozilla's fixed releases. Red Hat references indicate downstream Linux packages may also require vendor errata updates.

Exploitation context

The provided bundle does not show KEV listing or cited evidence of active exploitation. The CVSS vector indicates exploitation requires user interaction, likely by handling attacker-controlled web or message content.

Researcher notes

Evidence is limited to public CVE, Mozilla advisory links, Bugzilla, and Red Hat references. The sources identify the component and fixed releases but do not provide technical root cause details suitable for deeper exploitability assessment.

Mitigation direction

  • Upgrade Firefox, Firefox ESR, and Thunderbird to Mozilla's fixed versions or later.
  • Apply relevant Red Hat security errata for managed Linux environments.
  • Prioritize systems that browse untrusted websites or process external email.
  • Monitor Mozilla and distributor advisories for corrected package availability.
  • Do not rely on generic mitigations unless vendor guidance names them.

Validation and detection

  • Inventory Firefox, Firefox ESR, and Thunderbird versions across endpoints.
  • Confirm installed versions meet or exceed Mozilla's fixed releases.
  • Check Red Hat package status against linked RHSA advisories where applicable.
  • Review vulnerability scanner findings for CVE-2026-12289 after patching.
  • Confirm browser and mail client update policies cover all user profiles.
Prepared
Confidence
medium
Sources
12

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

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.

cwe · low confidence lookup

CWE-266: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
cwe · medium confidence lookup

CWE-269: Authorization and privilege behavior lookup

Authorization weaknesses can support privilege escalation and valid-account review, depending on exploit path. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
description · low confidence lookup

Privilege 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 lookup
cve · low confidence lookup

CVE-2026-12289 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
High
CVSS
8.8 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Official CVE source material

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.

2CVSS vectors
5Timeline events
2ADP providers
22Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: total

CVSS vector scores

2 official scores

We 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.

ScoreVersionSeverityVectorExploitImpactSource
8.8CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H2.85.9CISA-ADP
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H1.65.9redhat-SADP

Vulnerability scoring details

Base CVSS 3.1 score

8.8High
CVSS 3.1 vector shape for CVE-2026-12289Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. ADP timelineredhat-SADP

    Made public.

  3. CVE publishedCVE Program

    The CVE record was published.

  4. ADP timelineredhat-SADP

    Reported to Red Hat.

  5. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
cvssV3_1other:ssvc
redhat-SADPfirefox: thunderbird: Privilege escalation in the Graphics: WebRender component
other:Red Hat severity ratingcvssV3_1
  • 2026-06-16T14:02:01.382Z: Reported to Red Hat.
  • 2026-06-16T11:52:22.944Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
MozillaFirefox115.37, 140.12, 152Listed
MozillaThunderbird140.12, 152Listed
Weakness

CWE details

CWE-266CWE-269

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-266 · source CWE mapping

Incorrect Privilege Assignment

Incorrect Privilege Assignment represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs
CWE-269 · source CWE mapping

Improper Privilege Management

Improper Privilege Management represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs