LiveActive security incident?Get immediate response
CVE Record

CVE-2026-8091: Incorrect boundary conditions in the Audio/Video: Playback component

Incorrect boundary conditions in the Audio/Video: Playback component. This vulnerability was fixed in Firefox 150, Thunderbird 150, Firefox ESR 140.10.1, Thunderbird 140.10.1, and Firefox ESR 115.35.2.

CriticalCVSS 9.8Not KEV-listedUpdated
Discuss exposureBack to CVEs
Glexia's TakeAutomated analysiscritical

Security readout for executives and security teams

Plain-English summary

CVE-2026-8091 is a critical Mozilla flaw in audio/video playback handling. Mozilla says it is fixed in Firefox 150, Thunderbird 150, Firefox ESR 140.10.1, Thunderbird 140.10.1, and Firefox ESR 115.35.2. Systems running older relevant builds may face serious confidentiality, integrity, and availability risk.

Executive priority

Handle this as urgent patching. The issue is critical, affects common user-facing software, and carries a 9.8 CVSS score. No active exploitation is shown in the provided evidence, but delayed patching leaves high-impact exposure in browser and mail-client estates.

Technical view

The issue is described as incorrect boundary conditions in Mozilla's Audio/Video: Playback component, mapped to CWE-754 and CWE-805. The CVSS 3.1 score is 9.8 with network attack vector, low complexity, no privileges, no user interaction, unchanged scope, and high CIA impact.

Likely exposure

Exposure is most likely on endpoints, servers, or images running Firefox or Thunderbird builds that have not reached the listed fixed releases. Red Hat advisories indicate downstream package tracking and updates exist, so Linux fleet package state should be checked.

Exploitation context

The provided bundle marks KEV as false, and no cited source states active exploitation. The CVSS vector suggests severe theoretical exploitability, but the public source bundle does not provide exploit maturity, public proof-of-concept status, or detailed attack prerequisites.

Researcher notes

Public details are limited to component, weakness classes, CVSS, fixed releases, and vendor advisories. Avoid assuming affected version ranges beyond systems below the fixed releases. Mozilla Bugzilla and Red Hat trackers may contain access-controlled or evolving details not included here.

Mitigation direction

  • Update Firefox and Thunderbird to the Mozilla fixed releases or later.
  • Apply applicable Red Hat security errata for packaged Mozilla components.
  • Prioritize managed browsers and mail clients on internet-facing user endpoints.
  • Check Mozilla and OS vendor guidance for unsupported or blocked upgrade paths.
  • Retire or isolate systems that cannot receive vendor-supported updates.

Validation and detection

  • Inventory Firefox and Thunderbird versions across managed assets.
  • Compare installed versions with Mozilla's listed fixed release versions.
  • Confirm package managers show relevant Red Hat errata applied where applicable.
  • Run authenticated vulnerability scans for CVE-2026-8091 coverage.
  • Review exception lists for unmanaged browsers, portable apps, and stale images.
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-754: 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 · low confidence lookup

CWE-805: 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-2026-8091 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
25Source 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
7.5CVSS 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

9.8Critical
CVSS 3.1 vector shape for CVE-2026-8091Attack 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 Audio/Video: Playback component
other:Red Hat severity ratingcvssV3_1
  • 2026-05-07T13:00:55.414Z: Reported to Red Hat.
  • 2026-05-07T12:45:05.530Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
MozillaFirefox115.35.2, 140.10.1, 150Listed
MozillaThunderbird140.10.1, 150Listed
Weakness

CWE details

CWE-754CWE-805

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

CWE-754 · source CWE mapping

Improper Check for Unusual or Exceptional Conditions

Improper Check for Unusual or Exceptional Conditions represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs
CWE-805 · source CWE mapping

Buffer Access with Incorrect Length Value

Buffer Access with Incorrect Length Value represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs