Security readout for executives and security teams
Plain-English summary
A flaw in WebAssembly branch handling on arm64 systems can calculate the wrong destination when a branch table is unusually large. Mozilla rates the issue critically through the supplied CVSS data because successful exploitation could compromise confidentiality, integrity, and availability without privileges or user interaction.
Executive priority
Treat as an urgent arm64 patching issue because the reported impact is critical and network-reachable. Prioritize exposed browsers and email clients, while avoiding claims of an ongoing emergency: the supplied evidence does not establish active exploitation.
Technical view
On arm64, sufficiently large WebAssembly br_table instructions can place a label beyond the instruction’s representable range. Truncation can then produce an incorrect branch address. The supplied record maps this to CWE-1332 and reports CVSS 3.1 score 9.8. Mozilla fixed it across specified Firefox, Firefox ESR, and Thunderbird releases.
Likely exposure
Exposure is limited to arm64 installations of affected Firefox or Thunderbird versions capable of processing WebAssembly content. The bundle identifies fixed releases but does not provide complete vulnerable-version ranges, deployment prevalence, or platform-specific package status.
Exploitation context
The CVSS vector describes network reachability, low complexity, no privileges, and no required user interaction. However, the supplied bundle marks the CVE as absent from KEV and provides no evidence of active exploitation, public exploit availability, or observed attacks.
Researcher notes
The defect concerns arm64 branch-distance truncation during WebAssembly br_table handling, producing an incorrect computed branch address. The bundle does not establish the resulting memory-corruption primitive, reliable exploitability, affected version lower bounds, or attack telemetry. Validation should therefore emphasize architecture and fixed-version status rather than exploit reproduction.
Mitigation direction
- Update Firefox to 141 or the applicable ESR release: 115.26, 128.13, or 140.1.
- Update Thunderbird to 141, 128.13, or 140.1, as applicable.
- Check Mozilla or operating-system distributor guidance for package-specific release status.
- Prioritize arm64 endpoints and systems where browser or email content originates from untrusted sources.
Validation and detection
- Inventory Firefox and Thunderbird installations, recording architecture, edition, version, and package source.
- Confirm arm64 installations meet or exceed the applicable fixed release listed by Mozilla.
- Verify managed endpoints successfully received updates and restart applications where required.
- Review distributor advisories when operating-system package versions differ from Mozilla release numbering.
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-1332: 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-2025-8028 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=1971581CVE reference, mozilla
- https://www.mozilla.org/security/advisories/mfsa2025-56/CVE reference, mozilla
- https://www.mozilla.org/security/advisories/mfsa2025-57/CVE reference, mozilla
- https://www.mozilla.org/security/advisories/mfsa2025-58/CVE reference, mozilla
- https://www.mozilla.org/security/advisories/mfsa2025-59/CVE reference, mozilla
- https://www.mozilla.org/security/advisories/mfsa2025-61/CVE reference, mozilla
- https://www.mozilla.org/security/advisories/mfsa2025-62/CVE reference, mozilla
- https://www.mozilla.org/security/advisories/mfsa2025-63/CVE reference, mozilla
- https://lists.debian.org/debian-lts-announce/2025/07/msg00016.htmlCVE reference, CVE
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.
Improper Handling of Faults that Lead to Instruction Skips
Improper Handling of Faults that Lead to Instruction Skips represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.