How severe is CVE-2021-42125?

CVE-2021-42125 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-42125 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 82% (100th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-42125?

CVE-2021-42125 affects Ivanti Avalanche. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-42125?

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-2021-42125 published?

CVE-2021-42125 was published on 2021-12-07 and last updated on 2026-06-17.

CVE-2021-42125

CVE-2021-42125 is a high-severity vulnerability in Ivanti Avalanche with a CVSS 3.x base score of 8.8. Its EPSS exploit-prediction score of 82% places it in the 100th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-434.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v2: 6.5
EPSS exploit prediction: 82% (100th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-434
Affected product: Ivanti Avalanche
Published: 2021-12-07
Last modified: 2026-06-17

Description

An unrestricted file upload vulnerability exists in Ivanti Avalanche before 6.3.3 allows an attacker with access to the Inforail Service to write dangerous files.

Frequently asked questions

What is CVE-2021-42125?: An unrestricted file upload vulnerability exists in Ivanti Avalanche before 6.3.3 allows an attacker with access to the Inforail Service to write dangerous files.
How severe is CVE-2021-42125?: CVE-2021-42125 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-42125 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 82% (100th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-42125?: CVE-2021-42125 affects Ivanti Avalanche. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-42125?: 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-2021-42125 published?: CVE-2021-42125 was published on 2021-12-07 and last updated on 2026-06-17.

References

https://forums.ivanti.com/s/article/Security-Alert-CVE-s-Addressed-in-Avalanche-6-3-3

Affected products (1)

cpe:2.3:a:ivanti:avalanche:*:*:*:*:*:*:*:*

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