Security readout for executives and security teams
Plain-English summary
A memory-safety flaw in Firefox and Thunderbird could let remote content corrupt application memory, potentially compromising confidentiality, integrity, and availability. Mozilla has released fixed versions. Because the supplied CVSS score is 9.8 and no privileges or user interaction are required, organizations should update affected installations urgently.
Executive priority
Treat this as an urgent endpoint patching item. Accelerate browser and email-client updates, measure deployment coverage, and escalate systems that cannot reach fixed versions. There is no supplied evidence of active exploitation, but the potential impact and low-complexity rating justify priority action.
Technical view
CVE-2026-74944 is a use-after-free vulnerability (CWE-416) in Mozilla's DOM Core and HTML component. The supplied CVSS 3.1 vector is network-accessible, low complexity, unauthenticated, and requires no user interaction, with high confidentiality, integrity, and availability impact. Public technical details in the bundle are limited.
Likely exposure
Exposure likely includes Firefox and Thunderbird installations below the applicable fixed release: 154, ESR 140.14, or ESR 153.1. The source bundle does not provide complete affected-version boundaries, platform limitations, or configuration prerequisites, so inventory comparison against Mozilla's advisories is necessary.
Exploitation context
The bundle does not establish active exploitation, and the CVE is not listed as KEV. No public exploit status is provided. Nevertheless, the network-accessible, low-complexity CVSS assessment and memory-corruption class make prompt remediation appropriate without waiting for exploitation evidence.
Researcher notes
The record identifies a DOM Core and HTML use-after-free but provides no root-cause, trigger, platform, or exploitability details. The bundle's affected entries contain versions also described as fixed releases; therefore, they should not be interpreted as vulnerable versions. Use Mozilla advisories and Bugzilla for authoritative boundaries as disclosures develop.
Mitigation direction
- Update Firefox to 154, ESR 140.14, ESR 153.1, or a later supported release.
- Update Thunderbird to 154, 140.14, 153.1, or a later supported release.
- Prioritize internet-facing, broadly deployed, and privileged-user endpoints.
- Consult Mozilla advisories for product-channel details and any additional guidance.
Validation and detection
- Inventory installed Firefox and Thunderbird versions across managed and unmanaged endpoints.
- Confirm each installation meets or exceeds its applicable fixed release.
- Verify update deployment through endpoint-management and software-inventory reporting.
- Review Mozilla advisories for exact channel applicability and affected-version boundaries.
- Monitor Mozilla and CISA sources for changes in exploitation status.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
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-416: 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 lookupCVE-2026-74944 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- 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
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.
SSVC decision data
CVSS vector scores
1 official scoreWe 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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H3.95.9CISA-ADPVulnerability scoring details
Base CVSS 3.1 score
9.8CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://bugzilla.mozilla.org/show_bug.cgi?id=2057778CVE reference, mozilla
- https://www.mozilla.org/security/advisories/mfsa2026-74/CVE reference, mozilla
- https://www.mozilla.org/security/advisories/mfsa2026-76/CVE reference, mozilla
- https://www.mozilla.org/security/advisories/mfsa2026-77/CVE reference, mozilla
- https://www.mozilla.org/security/advisories/mfsa2026-78/CVE reference, mozilla
- https://www.mozilla.org/security/advisories/mfsa2026-79/CVE reference, mozilla
- https://www.mozilla.org/security/advisories/mfsa2026-80/CVE reference, mozilla
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Use After Free
Use After Free represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.