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CVE Record

CVE-2026-2759: Incorrect boundary conditions in the Graphics: ImageLib component

Incorrect boundary conditions in the Graphics: ImageLib 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-2026-2759 is a critical Mozilla Graphics: ImageLib boundary-condition flaw. The CVSS vector indicates network-reachable exploitation with no privileges or user interaction, with possible confidentiality, integrity, and availability impact. Mozilla states it is fixed in Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.

Executive priority

Treat this as an urgent browser and mail-client patching item. The technical score is critical and requires no user interaction in the CVSS model, but the provided sources do not confirm real-world exploitation.

Technical view

The issue is categorized as CWE-1384 in Mozilla's Graphics: ImageLib component. Available sources do not provide detailed root-cause mechanics. The CVSS 3.1 score is 9.8: AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Red Hat also tracks the issue and has published related advisories and VEX data.

Likely exposure

Organizations using Mozilla Firefox, Firefox ESR, or Thunderbird lines covered by the Mozilla advisories should assume exposure until fixed release or vendor-patched package status is confirmed. Linux distributions may receive patched builds through vendor advisories such as Red Hat RHSAs.

Exploitation context

The bundle marks CISA KEV status as false, and no cited source in the bundle states active exploitation. The high CVSS score indicates severe theoretical impact, but public exploitation status is not established from the provided evidence.

Researcher notes

Evidence is limited to component, CWE, CVSS, fixed versions, and vendor advisory metadata. Do not infer exploitability details beyond the CVSS vector. Bug-level implementation details are not present in the supplied bundle, so validation should focus on version and vendor package status.

Mitigation direction

  • Update Firefox to 148 or the applicable ESR fixed release.
  • Update Thunderbird to 148 or 140.8 where applicable.
  • Apply Red Hat or distribution security advisories for packaged Mozilla builds.
  • Check Mozilla and OS vendor guidance for any environment-specific mitigation.
  • Prioritize managed endpoints, VDI images, and server-side automation using browser components.

Validation and detection

  • Inventory Firefox, Firefox ESR, and Thunderbird versions across endpoints.
  • Confirm installed versions meet or exceed the fixed releases named by Mozilla.
  • Verify Linux packages map to patched vendor advisory builds.
  • Check vulnerability scanner plugins reference CVE-2026-2759 and current vendor data.
  • Document exceptions where business systems cannot update immediately.
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-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.

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cve · low confidence lookup

CVE-2026-2759 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
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
7.5CVSS 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-2026-2759Attack 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 Graphics: ImageLib component
other:Red Hat severity ratingcvssV3_1
  • 2026-02-24T14:03:27.889Z: Reported to Red Hat.
  • 2026-02-24T13:32:59.173Z: 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.

CWE-1384 · source CWE mapping

Improper Handling of Physical or Environmental Conditions

Improper Handling of Physical or Environmental Conditions represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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