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CVE Record

CVE-2026-12328: Memory safety bugs fixed in Firefox ESR 115.37, Firefox ESR 140.12, Thunderbird ESR 140.12, Firefox 152 and Thunderbird 152

Memory safety bugs present in Firefox ESR 115.36, Firefox ESR 140.11, Thunderbird ESR 140.11, Firefox 151 and Thunderbird 151. 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 152, Firefox ESR 140.12, Firefox ESR 115.37, Thunderbird 152, and Thunderbird 140.12.

HighCVSS 8.1Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

Mozilla fixed a set of memory safety bugs in Firefox and Thunderbird. Mozilla says some showed memory corruption and could, with enough effort, be exploited to run arbitrary code. This is high risk for organizations running the named older browser or mail client versions.

Executive priority

Treat this as a high-priority client patching item, not an emergency unless new exploitation evidence appears. Update managed browser and mail client fleets quickly, with extra focus on externally exposed users and systems handling untrusted content.

Technical view

CVE-2026-12328 covers memory safety defects mapped to CWE-120 and CWE-825. Affected versions include Firefox 151, Firefox ESR 115.36/140.11, Thunderbird 151, and Thunderbird ESR 140.11. Fixed releases are Firefox 152, Firefox ESR 115.37/140.12, Thunderbird 152, and Thunderbird ESR 140.12. CVSS is 8.1.

Likely exposure

Exposure is likely on desktops, VDI images, servers, or managed Linux systems where vulnerable Firefox or Thunderbird versions remain installed. Email-heavy environments using Thunderbird deserve priority because malicious content may be processed in a mail client.

Exploitation context

The bundle does not show CISA KEV listing or confirmed active exploitation. Mozilla states some bugs showed memory corruption and could potentially be exploited for arbitrary code execution. Public bug details may be limited, so assume exploitability is plausible but not proven in the supplied evidence.

Researcher notes

The source bundle identifies memory corruption evidence but does not separate individual bug impact details. Avoid assuming exploit primitives, affected platforms beyond Mozilla/Red Hat references, or active exploitation. Research should focus on version verification, advisory mapping, and vendor patch status.

Mitigation direction

  • Upgrade Firefox to 152, ESR 140.12, or ESR 115.37 as applicable.
  • Upgrade Thunderbird to 152 or ESR 140.12 as applicable.
  • Apply relevant Red Hat security errata on Red Hat-managed systems.
  • Prioritize systems that browse untrusted sites or process external email.
  • Check Mozilla and OS vendor guidance for any environment-specific remediation.

Validation and detection

  • Inventory Firefox and Thunderbird versions across endpoints and managed images.
  • Flag Firefox 151, ESR 115.36, ESR 140.11, Thunderbird 151, and ESR 140.11.
  • Confirm upgraded systems report the fixed release channel versions.
  • Review Red Hat advisory applicability for subscribed Red Hat assets.
  • Monitor vulnerability scanners for CVE-2026-12328 closure after patching.
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-120: 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-825: 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
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.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2026-12328 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
8.1 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:H/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
22Source 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
8.1CVSS 3.1HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H2.25.9CISA-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

8.1High
CVSS 3.1 vector shape for CVE-2026-12328Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:H/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: Memory safety bugs fixed in Firefox ESR 115.37, Firefox ESR 140.12, Thunderbird ESR 140.12, Firefox 152 and Thunderbird 152
other:Red Hat severity ratingcvssV3_1
  • 2026-06-16T14:01:30.159Z: Reported to Red Hat.
  • 2026-06-16T11:53:01.835Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
MozillaFirefox115.37, 140.12, 152Listed
MozillaThunderbird140.12, 152Listed
Weakness

CWE details

CWE-120CWE-825

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

CWE-120 · source CWE mapping

Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs
CWE-825 · source CWE mapping

Expired Pointer Dereference

Expired Pointer Dereference represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs