How severe is CVE-2025-9179?

CVE-2025-9179 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2025-9179 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (41st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-9179?

CVE-2025-9179 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-2025-9179?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

Does CVE-2025-9179 have an EU (EUVD) identifier?

Yes. CVE-2025-9179 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-25246.

When was CVE-2025-9179 published?

CVE-2025-9179 was published on 2025-08-19 and last updated on 2026-06-17.

CVE-2025-9179

CVE-2025-9179 is a critical-severity vulnerability in Mozilla Firefox with a CVSS 3.x base score of 9.8. 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: Critical (CVSS 3.x base score 9.8)
EPSS exploit prediction: 1% (41st percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-25246
Weakness: CWE-119
Affected product: Mozilla Firefox
Published: 2025-08-19
Last modified: 2026-06-17

Description

An attacker was able to perform memory corruption in the GMP process which processes encrypted media. This process is also heavily sandboxed, but represents slightly different privileges from the content process. This vulnerability was fixed in Firefox 142, Firefox ESR 115.27, Firefox ESR 128.14, Firefox ESR 140.2, Thunderbird 142, Thunderbird 128.14, and Thunderbird 140.2.

Frequently asked questions

What is CVE-2025-9179?: An attacker was able to perform memory corruption in the GMP process which processes encrypted media. This process is also heavily sandboxed, but represents slightly different privileges from the content process. This vulnerability was fixed in Firefox 142, Firefox ESR 115.27, Firefox ESR 128.14, Firefox ESR 140.2, Thunderbird 142, Thunderbird 128.14, and Thunderbird 140.2.
How severe is CVE-2025-9179?: CVE-2025-9179 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2025-9179 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (41st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-9179?: CVE-2025-9179 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-2025-9179?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2025-9179 have an EU (EUVD) identifier?: Yes. CVE-2025-9179 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-25246.
When was CVE-2025-9179 published?: CVE-2025-9179 was published on 2025-08-19 and last updated on 2026-06-17.

References

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:*:*:*:*:-:*:*:*

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