Security readout for executives and security teams
Plain-English summary
A critical integer-overflow flaw in Mozilla’s graphics processing could compromise confidentiality, integrity, and availability. Firefox and Thunderbird installations not updated to their applicable fixed release may be at risk. The supplied evidence does not define precise vulnerable version ranges.
Executive priority
Treat as an urgent patching priority because the supplied rating is critical and potential impact spans data theft, modification, and disruption. Confirm coverage promptly, while recognizing that the provided sources do not establish active exploitation.
Technical view
CVE-2026-74964 is a CWE-190 integer overflow in Mozilla’s Graphics component. The supplied CVSS 3.1 score is 9.8, describing network-reachable, low-complexity exploitation without privileges or user interaction, with potentially high confidentiality, integrity, and availability impact. No further root-cause or exploitability details are provided.
Likely exposure
Potential exposure exists wherever affected Firefox or Thunderbird release channels remain below their applicable fixes: 154, ESR 140.14, or ESR 153.1. The bundle lists these as fixed versions, despite also placing them under “affected”; precise vulnerable ranges are therefore incomplete.
Exploitation context
The bundle says this CVE is not in KEV and provides no cited evidence of active exploitation or a public exploit. Its critical CVSS characteristics indicate serious theoretical risk, but observed exploitation cannot be claimed from the supplied evidence.
Researcher notes
The public bundle identifies only CWE-190 and the Graphics component; it provides no crash primitive, memory-corruption consequence, affected code path, or vulnerable version boundaries. Researchers should avoid interpreting the listed fixed releases as affected versions and consult Mozilla’s linked advisories and Bugzilla record for authorized technical detail.
Mitigation direction
- Update Firefox to 154, ESR 140.14, ESR 153.1, or a later applicable release.
- Update Thunderbird to 154, 140.14, 153.1, or a later applicable release.
- Prioritize internet-facing, broadly deployed, and privileged-user endpoints.
- Consult the applicable Mozilla advisory for channel-specific deployment guidance.
Validation and detection
- Inventory installed Firefox and Thunderbird versions across managed endpoints.
- Confirm each installation meets or exceeds its applicable fixed release.
- Verify update-management reporting against endpoint-level version evidence.
- Monitor Mozilla advisories and internal telemetry for new exploitation information.
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-190: 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-2026-74964 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=2053327CVE 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.
Integer Overflow or Wraparound
Integer Overflow or Wraparound represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.