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CVE Record

CVE-2026-2757: Incorrect boundary conditions in the WebRTC: Audio/Video component

Incorrect boundary conditions in the WebRTC: Audio/Video component. This vulnerability was fixed in Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.

CriticalCVSS 9.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysiscritical

Security readout for executives and security teams

Plain-English summary

CVE-2026-2757 is a critical Mozilla WebRTC audio/video boundary-condition flaw. Mozilla states it is fixed in Firefox 148, Firefox ESR 115.33/140.8, Thunderbird 148, and Thunderbird 140.8. It could affect confidentiality, integrity, and availability. The provided sources do not show CISA KEV listing or confirmed active exploitation.

Executive priority

Prioritize patching in normal emergency browser and email-client update cycles. The severity is critical and the affected software is widely deployed, but the supplied sources do not confirm active exploitation.

Technical view

The issue is described as incorrect boundary conditions in Mozilla’s WebRTC Audio/Video component, mapped to CWE-1384. CVSS 3.1 is 9.8 with network attack vector, low complexity, no privileges, and no user interaction. Public technical detail is limited in the provided sources.

Likely exposure

Organizations using Firefox, Firefox ESR, or Thunderbird versions older than the fixed releases are the primary exposure. Linux environments using Red Hat-packaged Mozilla components should check applicable RHSA advisories. Exposure depends on installed browser/mail-client versions and package provenance.

Exploitation context

The CVSS vector indicates remote, unauthenticated, low-complexity risk with high impact. However, the provided sources do not include exploit details, proof-of-concept availability, or confirmed active exploitation. KEV is marked false in the supplied data.

Researcher notes

Public detail is sparse beyond the component, weakness class, CVSS vector, and fixed releases. Avoid assuming exploit mechanics from the WebRTC label alone. Use Mozilla advisories and Red Hat errata for authoritative version and package validation.

Mitigation direction

  • Update Firefox to 148 or the applicable fixed ESR release.
  • Update Thunderbird to 148 or 140.8 as applicable.
  • Apply relevant Red Hat RHSA updates for packaged Mozilla components.
  • If fixed builds are unavailable, follow current Mozilla or vendor guidance.

Validation and detection

  • Inventory Firefox, Firefox ESR, and Thunderbird versions across endpoints.
  • Confirm installed versions meet or exceed Mozilla fixed releases.
  • Check Red Hat systems against applicable RHSA package versions.
  • Review vulnerability scanner results for CVE-2026-2757 after patching.
  • Monitor Mozilla and Red Hat advisories for updates.
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-1384: 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
cve · low confidence lookup

CVE-2026-2757 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
Critical
CVSS
9.8 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/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: yesTechnical 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
9.8CVSS 3.1CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H3.95.9CISA-ADP
7.1CVSS 3.1HighCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:L1.65.5redhat-SADP

Vulnerability scoring details

Base CVSS 3.1 score

9.8Critical
CVSS 3.1 vector shape for CVE-2026-2757Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/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: Incorrect boundary conditions in the WebRTC: Audio/Video component
other:Red Hat severity ratingcvssV3_1
  • 2026-02-24T14:04:32.278Z: Reported to Red Hat.
  • 2026-02-24T13:32:57.740Z: 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-1384

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