Answer in brief
CVE-2026-12328 records a High severity (CVSS 8.1) vulnerability in Memory safety bugs fixed in Firefox ESR 115.37, Firefox ESR 140.12, Thunderbird ESR 140.12, Firefox 152 and Thunderbird 152. The current sources do not mark it as known exploited. The current feed maps Red Hat/rhel10/firefox-flatpak (generic), Red Hat/rhel10/thunderbird-flatpak (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 8.1. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Red Hat/rhel10/firefox-flatpak (generic), Red Hat/rhel10/thunderbird-flatpak (generic). Check affected ranges and fixed versions before updating.
| Product | Affected versions | Fixed versions |
|---|---|---|
| cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:* | Not reported | Not reported |
| cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:* | Not reported | Not reported |
| cpe:2.3:a:mozilla:thunderbird:*:*:*:*:-:*:*:* | Not reported | Not reported |
| cpe:2.3:a:mozilla:thunderbird:*:*:*:*:esr:*:*:* | Not reported | Not reported |
| Package | Affected range | Fixed version |
|---|---|---|
| Red Hat/rhel10/firefox-flatpakgeneric | * | Not reported |
| Red Hat/rhel10/thunderbird-flatpakgeneric | * | Not reported |
Published upstream
Jun 16, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 26, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jun 30, 2026
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.
Quoted source text, attributed separately from HOL analysis.