CVE•Published 2025-04-29•Modified 2026-04-13•1 article on news•6 live references•NVD data

CVE-2025-4091Mozilla · Firefox

Vulnerability data via NVD (ingested)

CVSS v3.1

8.1

HIGH

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS percentile

—

Weaknesses (CWE)

CWE-119Improper Restriction of Operations within the Bounds of a Memory Buffer

Description

Memory safety bugs present in Firefox 137, Thunderbird 137, Firefox ESR 128.9, and Thunderbird 128.9. 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 138, Firefox ESR 128.10, Thunderbird 138, and Thunderbird 128.10.

Timeline

Published 2025-04-29

Modified 2026-04-13

External references

NVD MITRE Exploit-DB GitHub PoC trickest/cve VulnCheck

Search for exposed instances

Shodan + Censys queries derived from NVD's CPE data. The vuln tag catches assets Shodan has explicitly linked to this CVE; the product / banner fingerprints find exposed instances even when the vuln tag was never applied (which is common).

Shodan · vuln tag0 hosts

vuln:CVE-2025-4091

Hosts Shodan has explicitly fingerprinted as vulnerable.

Shodan · product

product:"Mozilla Firefox"

All exposed Mozilla Firefox instances — cross-reference with the CVE's affected-version range.

Shodan · banner/body mention

http.html:"Firefox"

HTTP body or banner mentions "Firefox" — catches deploys Shodan didn't identify as a product.

More intel sources (5)

Shodan report

vuln:CVE-2025-4091