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CVE Record

CVE-2026-2792: Memory safety bugs fixed in Firefox ESR 140.8, Thunderbird ESR 140.8, Firefox 148 and Thunderbird 148

Memory safety bugs present in Firefox ESR 140.7, Thunderbird ESR 140.7, Firefox 147 and Thunderbird 147. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 148, 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

This is a critical Mozilla memory-safety issue affecting Firefox and Thunderbird releases before the fixed versions. Mozilla says the bugs showed memory corruption and could potentially be exploited to run arbitrary code with enough effort. Treat it as urgent endpoint patching, especially where Firefox or Thunderbird is used for web or email workflows.

Executive priority

High priority for rapid patching. This is a critical client-side memory corruption issue with possible code execution impact, even though the supplied evidence does not show active exploitation. Address it through standard browser and mail-client update channels and confirm coverage across managed endpoints.

Technical view

CVE-2026-2792 covers multiple memory-safety bugs, mapped to CWE-787, fixed in Firefox 148, Firefox ESR 140.8, Thunderbird 148, and Thunderbird ESR 140.8. Mozilla states affected prior releases include Firefox 147, Firefox ESR 140.7, Thunderbird 147, and Thunderbird ESR 140.7. CVSS is 9.8: network, low complexity, no privileges, no user interaction, high impact.

Likely exposure

Exposure is likely on endpoints and managed Linux fleets running affected Firefox or Thunderbird builds, including Red Hat-distributed packages referenced by errata. The source bundle does not identify a vulnerable server component or non-Mozilla products beyond distribution packaging.

Exploitation context

The provided sources do not show CISA KEV listing or confirmed active exploitation. Mozilla’s wording indicates memory corruption with presumed arbitrary-code potential, not a public exploit report. Risk remains high because browsers and mail clients routinely process untrusted content.

Researcher notes

Evidence is limited to aggregate memory-safety bug advisories and Red Hat packaging references. The Bugzilla list is cited, but the bundle does not provide exploit details, crash specifics, or per-bug root-cause analysis. Do not infer affected forks or exploit availability without additional vendor evidence.

Mitigation direction

  • Upgrade Firefox to 148 or Firefox ESR 140.8 or later.
  • Upgrade Thunderbird to 148 or Thunderbird ESR 140.8 or later.
  • Apply relevant Red Hat security errata for packaged Firefox or Thunderbird.
  • Check Mozilla and distribution guidance for any environment-specific mitigations.
  • Prioritize managed endpoints used for web browsing or email handling.

Validation and detection

  • Inventory Firefox and Thunderbird versions across workstations and servers.
  • Confirm affected prior releases are no longer present.
  • Verify Red Hat systems have applicable RHSA updates installed.
  • Review vulnerability scanner results against CVE-2026-2792 after patching.
  • Monitor Mozilla and Red Hat advisories for follow-up 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-787: 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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description · low confidence lookup

Execution behavior lookup

The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

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cve · low confidence lookup

CVE-2026-2792 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
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
34Source 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
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-2026-2792Attack 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
other:ssvccvssV3_1
redhat-SADPfirefox: thunderbird: Memory safety bugs fixed in Firefox ESR 140.8, Thunderbird ESR 140.8, Firefox 148 and Thunderbird 148
other:Red Hat severity ratingcvssV3_1
  • 2026-02-24T14:04:09.479Z: Reported to Red Hat.
  • 2026-02-24T13:33:22.842Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
MozillaFirefox140.8, 148Listed
MozillaThunderbird140.8, 148Listed
Weakness

CWE details

CWE-787

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

CWE-787 · source CWE mapping

Out-of-bounds Write

Out-of-bounds Write represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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