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CVE Record

CVE-2026-2770: Use-after-free in the DOM: Bindings (WebIDL) component

Use-after-free in the DOM: Bindings (WebIDL) component. This vulnerability was fixed in Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.

HighCVSS 8.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2026-2770 is a high-severity Mozilla memory-safety flaw in DOM WebIDL bindings. A user would need to interact with attacker-controlled web or email content, but successful exploitation could compromise confidentiality, integrity, and availability. Mozilla says it is fixed in current Firefox, Firefox ESR, and Thunderbird releases named in the advisories.

Executive priority

Treat this as a high-priority endpoint patching item, especially for users who browse the web or process external email. There is no supplied evidence of active exploitation, but the impact rating supports prompt remediation through standard browser and mail-client update channels.

Technical view

The issue is a CWE-416 use-after-free in Mozilla's DOM: Bindings (WebIDL) component. The CVSS 3.1 score is 8.8 with network attack vector, low complexity, no privileges, and required user interaction. Fixed releases include Firefox 148, ESR 115.33, ESR 140.8, Thunderbird 148, and Thunderbird 140.8.

Likely exposure

Exposure is most likely on endpoints or servers running Mozilla Firefox, Firefox ESR, or Thunderbird that have not been updated to the fixed releases. Linux distributions using vendor-packaged Mozilla builds should also track Red Hat or distribution-specific errata where applicable.

Exploitation context

The bundle does not show CISA KEV listing or cited evidence of active exploitation. The CVSS vector indicates remote delivery is plausible but requires user interaction. No public exploit details are provided in the supplied sources.

Researcher notes

Source detail is limited to advisory-level information: component, weakness type, CVSS, and fixed versions. Avoid claiming exploitability beyond the CVSS and user-interaction requirement. Bugzilla and vendor advisories should be monitored for any later disclosure of technical details or exploitation evidence.

Mitigation direction

  • Update Firefox to version 148 or the supported fixed ESR release.
  • Update Thunderbird to version 148 or 140.8 where applicable.
  • Apply relevant Red Hat errata for packaged Mozilla builds.
  • Check Mozilla and OS vendor advisories for environment-specific guidance.
  • Prioritize browser and mail-client updates on high-risk user workstations.

Validation and detection

  • Inventory installed Firefox, Firefox ESR, and Thunderbird versions across endpoints.
  • Confirm versions meet or exceed the fixed releases named by Mozilla.
  • Verify Linux package status against applicable Red Hat or distribution errata.
  • Run vulnerability scanning after updates to confirm CVE-2026-2770 is cleared.
  • Check endpoint management reports for update failures or unmanaged installations.
Prepared
Confidence
high
Sources
11

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-416: 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.

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cve · low confidence lookup

CVE-2026-2770 mapping review

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

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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
35Source 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-2026-2770Attack 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: Use-after-free in the DOM: Bindings (WebIDL) component
other:Red Hat severity ratingcvssV3_1
  • 2026-02-24T14:05:45.874Z: Reported to Red Hat.
  • 2026-02-24T13:33:07.898Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
MozillaFirefox115.33, 140.8, 148Listed
MozillaThunderbird140.8, 148Listed
Weakness

CWE details

CWE-416

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

CWE-416 · source CWE mapping

Use After Free

Use After Free represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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