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CVE Record

CVE-2026-8975: Memory safety bugs fixed in Firefox ESR 115.36, Firefox ESR 140.11 and Firefox 151

Memory safety bugs present in Firefox ESR 115.35, Firefox ESR 140.10 and Firefox 150. 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 151, Firefox ESR 115.36, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.

HighCVSS 8.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2026-8975 covers Mozilla memory safety bugs that could corrupt memory and may allow arbitrary code execution if a user opens malicious content. Mozilla fixed it in Firefox 151, Firefox ESR 115.36/140.11, Thunderbird 151, and Thunderbird 140.11. Treat unpatched browser and mail clients as business-relevant exposure.

Executive priority

Patch on a normal high-priority browser security timeline, accelerated for exposed workstations and email-heavy roles. There is no sourced active exploitation signal, but the impact could include code execution after user interaction.

Technical view

The issue is a high-severity memory corruption class vulnerability, mapped to CWE-119 and CWE-787, with CVSS 3.1 score 8.8. The vector is network-reachable, low complexity, no privileges required, but requires user interaction. Mozilla states some bugs showed memory corruption and could plausibly be exploitable for arbitrary code execution.

Likely exposure

Organizations are exposed where Firefox ESR 115.35, Firefox ESR 140.10, Firefox 150, or Mozilla clients below the listed fixed Thunderbird versions remain installed. Linux environments using Red Hat-packaged builds should check the referenced RHSA advisories for applicability.

Exploitation context

The source bundle does not show CISA KEV listing or cited evidence of active exploitation. Risk remains meaningful because browser and email-client memory corruption can be triggered through attacker-controlled web or message content when a user interacts.

Researcher notes

Mozilla grouped several memory safety bugs under this CVE, with Bugzilla references but limited public technical detail in the bundle. Avoid assuming exploitability beyond Mozilla's statement that some memory corruption could be exploitable with enough effort.

Mitigation direction

  • Update Firefox to 151 or ESR 115.36/140.11 as applicable.
  • Update Thunderbird to 151 or 140.11 as applicable.
  • Apply relevant Red Hat RHSA packages where Mozilla software is OS-managed.
  • Check Mozilla and vendor advisories for platform-specific guidance.
  • Prioritize managed endpoint browser and email client patch compliance.

Validation and detection

  • Inventory Firefox and Thunderbird versions across endpoints and servers.
  • Confirm installed versions meet or exceed Mozilla's fixed releases.
  • Check Red Hat errata applicability for each affected distribution.
  • Verify patch deployment through endpoint management or package inventory.
  • Monitor vendor advisories for revised affected-version details.
Prepared
Confidence
high
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-119: 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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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.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2026-8975 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
31Source 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-2026-8975Attack 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: Memory safety bugs fixed in Firefox ESR 115.36, Firefox ESR 140.11 and Firefox 151
other:Red Hat severity ratingcvssV3_1
  • 2026-05-19T14:01:22.742Z: Reported to Red Hat.
  • 2026-05-19T12:30:24.616Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
MozillaFirefox115.36, 140.11, 151Listed
MozillaThunderbird140.11, 151Listed
Weakness

CWE details

CWE-119CWE-787

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