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CVE Record

CVE-2026-2774: Integer overflow in the Audio/Video component

Integer overflow in the Audio/Video 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-2026-2774 is a high-severity Mozilla Firefox and Thunderbird flaw in audio/video handling. A user interaction is required, but no login is needed. Mozilla says it was fixed in Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.

Executive priority

Treat this as a near-term browser and mail-client patching priority. There is no sourced evidence of active exploitation, but the severity and impact justify prompt fleet-wide updates, especially on internet-facing user workstations and managed Linux estates.

Technical view

The issue is an integer overflow in Mozilla's Audio/Video component, classified as CWE-190. The CVSS 3.1 score is 8.8 with network attack vector, low complexity, no privileges required, user interaction required, unchanged scope, and high confidentiality, integrity, and availability impact.

Likely exposure

Organizations are most exposed where managed endpoints or servers still run Firefox or Thunderbird below the fixed Mozilla releases. Red Hat references and errata indicate downstream Linux package exposure may also matter for environments using Red Hat-supported builds.

Exploitation context

The provided sources do not state active exploitation, and the CVE is not marked KEV. The risk is still material because exploitation is network-reachable with low complexity, but it requires user interaction with affected audio/video handling.

Researcher notes

Evidence is limited to advisory-level details. The Bugzilla reference is public, but the supplied bundle does not provide root-cause depth beyond integer overflow in Audio/Video. Avoid assuming exploitability details beyond the CVSS vector and Mozilla's fixed-version statements.

Mitigation direction

  • Update Firefox to 148, ESR 115.33, ESR 140.8, or later supported fixed builds.
  • Update Thunderbird to 148, 140.8, or later supported fixed builds.
  • Apply relevant Red Hat security errata where using Red Hat-packaged Mozilla software.
  • Check Mozilla and OS vendor advisories for environment-specific package names and backports.
  • Prioritize managed browser and mail-client fleets before lower-use systems.

Validation and detection

  • Inventory Firefox and Thunderbird versions across endpoints and server images.
  • Confirm installed builds match or exceed the fixed versions named by Mozilla.
  • Review Red Hat errata applicability for deployed Red Hat products.
  • Check vulnerability scanners for CVE-2026-2774 after patch deployment.
  • Document any unsupported or unmanaged systems that cannot be updated promptly.
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-190: 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-2026-2774 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-2026-2774Attack 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: Integer overflow in the Audio/Video component
other:Red Hat severity ratingcvssV3_1
  • 2026-02-24T14:02:20.295Z: Reported to Red Hat.
  • 2026-02-24T13:33:10.821Z: 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-190

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

CWE-190 · source CWE mapping

CWE mapping pending import

This CVE carries a CWE mapping that will resolve to a full Glexia CWE intelligence page after the official CWE import is complete.

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