How severe is CVE-2022-34476?

CVE-2022-34476 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-2022-34476 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (49th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2022-34476?

CVE-2022-34476 affects Mozilla Firefox. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2022-34476?

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.

When was CVE-2022-34476 published?

CVE-2022-34476 was published on 2022-12-22 and last updated on 2026-06-17.

CVE-2022-34476

CVE-2022-34476 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-20.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
EPSS exploit prediction: 1% (49th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
Affected product: Mozilla Firefox
Published: 2022-12-22
Last modified: 2026-06-17

Description

ASN.1 parsing of an indefinite SEQUENCE inside an indefinite GROUP could have resulted in the parser accepting malformed ASN.1. This vulnerability affects Firefox < 102.

Frequently asked questions

What is CVE-2022-34476?: ASN.1 parsing of an indefinite SEQUENCE inside an indefinite GROUP could have resulted in the parser accepting malformed ASN.1. This vulnerability affects Firefox < 102.
How severe is CVE-2022-34476?: CVE-2022-34476 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-2022-34476 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (49th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2022-34476?: CVE-2022-34476 affects Mozilla Firefox. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2022-34476?: 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.
When was CVE-2022-34476 published?: CVE-2022-34476 was published on 2022-12-22 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*

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