What is CVE-2022-31739?

When downloading files on Windows, the % character was not escaped, which could have lead to a download incorrectly being saved to attacker-influenced paths that used variables such as %HOMEPATH% or %APPDATA%. *This bug only affects Firefox for Windows. Other operating systems are unaffected.*. This vulnerability affects Thunderbird < 91.10, Firefox < 101, and Firefox ESR < 91.10.

How severe is CVE-2022-31739?

CVE-2022-31739 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-2022-31739 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (47th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2022-31739?

CVE-2022-31739 primarily affects Mozilla Firefox. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2022-31739?

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.

When was CVE-2022-31739 published?

CVE-2022-31739 was published on 2022-12-22 and last updated on 2026-06-17.

CVE-2022-31739

Q: How severe is CVE-2022-31739?

CVE-2022-31739 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.

Q: Is CVE-2022-31739 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (47th percentile), an estimate of the probability of exploitation in the next 30 days.

Q: What products are affected by CVE-2022-31739?

CVE-2022-31739 primarily affects Mozilla Firefox. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

Q: How do I fix CVE-2022-31739?

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.

Q: When was CVE-2022-31739 published?

CVE-2022-31739 was published on 2022-12-22 and last updated on 2026-06-17.

CVE-2022-31739 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-73.

Key facts

Severity: High (CVSS 3.x base score 8.8)
EPSS exploit prediction: 1% (47th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-73
Affected product: Mozilla Firefox
Published: 2022-12-22
Last modified: 2026-06-17

Description

When downloading files on Windows, the % character was not escaped, which could have lead to a download incorrectly being saved to attacker-influenced paths that used variables such as %HOMEPATH% or %APPDATA%.<br>*This bug only affects Firefox for Windows. Other operating systems are unaffected.*. This vulnerability affects Thunderbird < 91.10, Firefox < 101, and Firefox ESR < 91.10.

Frequently asked questions

What is CVE-2022-31739?: When downloading files on Windows, the % character was not escaped, which could have lead to a download incorrectly being saved to attacker-influenced paths that used variables such as %HOMEPATH% or %APPDATA%.<br>*This bug only affects Firefox for Windows. Other operating systems are unaffected.*. This vulnerability affects Thunderbird < 91.10, Firefox < 101, and Firefox ESR < 91.10.
How severe is CVE-2022-31739?: CVE-2022-31739 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-2022-31739 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (47th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2022-31739?: CVE-2022-31739 primarily affects Mozilla Firefox. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2022-31739?: 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.
When was CVE-2022-31739 published?: CVE-2022-31739 was published on 2022-12-22 and last updated on 2026-06-17.

References

Affected products (3)

cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*

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