CVE-2025-8034
CVE-2025-8034 is a high-severity vulnerability in Mozilla Firefox with a CVSS 3.x base score of 8.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-119.
Key facts
- Severity: High (CVSS 3.x base score 8.8)
- EPSS exploit prediction: 0% (30th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2025-22361
- Weakness: CWE-119
- Affected product: Mozilla Firefox
- Published:
- Last modified:
Description
Memory safety bugs present in Firefox ESR 115.25, Firefox ESR 128.12, Thunderbird ESR 128.12, Firefox ESR 140.0, Thunderbird ESR 140.0, Firefox 140 and Thunderbird 140. 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 141, Firefox ESR 115.26, Firefox ESR 128.13, Firefox ESR 140.1, Thunderbird 141, Thunderbird 128.13, and Thunderbird 140.1.
Frequently asked questions
- What is CVE-2025-8034?
- Memory safety bugs present in Firefox ESR 115.25, Firefox ESR 128.12, Thunderbird ESR 128.12, Firefox ESR 140.0, Thunderbird ESR 140.0, Firefox 140 and Thunderbird 140. 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 141, Firefox ESR 115.26, Firefox ESR 128.13, Firefox ESR 140.1, Thunderbird 141, Thunderbird 128.13, and Thunderbird 140.1.
- How severe is CVE-2025-8034?
- CVE-2025-8034 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
- Is CVE-2025-8034 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (30th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2025-8034?
- CVE-2025-8034 primarily affects Mozilla Firefox. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
- How do I fix CVE-2025-8034?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- Does CVE-2025-8034 have an EU (EUVD) identifier?
- Yes. CVE-2025-8034 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-22361.
- When was CVE-2025-8034 published?
- CVE-2025-8034 was published on 2025-07-22 and last updated on 2026-06-17.
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=1970422
- https://www.mozilla.org/security/advisories/mfsa2025-56/
- https://www.mozilla.org/security/advisories/mfsa2025-57/
- https://www.mozilla.org/security/advisories/mfsa2025-58/
- https://www.mozilla.org/security/advisories/mfsa2025-59/
- https://www.mozilla.org/security/advisories/mfsa2025-61/
- https://www.mozilla.org/security/advisories/mfsa2025-62/
- https://www.mozilla.org/security/advisories/mfsa2025-63/
- https://lists.debian.org/debian-lts-announce/2025/07/msg00016.html
Affected products (4)
- cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*
- cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*
- cpe:2.3:a:mozilla:thunderbird:*:*:*:*:esr:*:*:*
- cpe:2.3:a:mozilla:thunderbird:*:*:*:*:-:*:*:*
More vulnerabilities in Mozilla Firefox
- CVE-2026-4725 — Critical (CVSS 10.0): Sandbox escape due to use-after-free in the Graphics: Canvas2D component. This vulnerability was fixed in Firefox 149…
- CVE-2026-4692 — Critical (CVSS 10.0): Sandbox escape in the Responsive Design Mode component. This vulnerability was fixed in Firefox 149, Firefox ESR…
- CVE-2026-4689 — Critical (CVSS 10.0): Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM component. This vulnerability was…
- CVE-2026-4688 — Critical (CVSS 10.0): Sandbox escape due to use-after-free in the Disability Access APIs component. This vulnerability was fixed in Firefox…
- CVE-2026-2778 — Critical (CVSS 10.0): Sandbox escape due to incorrect boundary conditions in the DOM: Core & HTML component. This vulnerability was fixed in…
- CVE-2026-2776 — Critical (CVSS 10.0): Sandbox escape due to incorrect boundary conditions in the Telemetry component in External Software. This vulnerability…
All CVEs affecting Mozilla Firefox →
Other CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) vulnerabilities
- CVE-2026-2778 — Critical (CVSS 10.0): Sandbox escape due to incorrect boundary conditions in the DOM: Core & HTML component. This vulnerability was fixed in…
- CVE-2026-2776 — Critical (CVSS 10.0): Sandbox escape due to incorrect boundary conditions in the Telemetry component in External Software. This vulnerability…
- CVE-2025-1866 — Critical (CVSS 10.0): Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability in warmcat libwebsockets allows…
- CVE-2022-27625 — Critical (CVSS 10.0): A vulnerability regarding improper restriction of operations within the bounds of a memory buffer is found in the…
- CVE-2022-27624 — Critical (CVSS 10.0): A vulnerability regarding improper restriction of operations within the bounds of a memory buffer is found in the…
- CVE-2020-11896 — Critical (CVSS 10.0): The Treck TCP/IP stack before 6.0.1.66 allows Remote Code Execution, related to IPv4 tunneling.