How severe is CVE-2020-8165?

CVE-2020-8165 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-2020-8165 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 46% (99th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-8165?

CVE-2020-8165 primarily affects Rubyonrails Rails. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-8165?

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-2020-8165 published?

CVE-2020-8165 was published on 2020-06-19 and last updated on 2026-06-17.

CVE-2020-8165

CVE-2020-8165 is a critical-severity vulnerability in Rubyonrails Rails with a CVSS 3.x base score of 9.8. Its EPSS exploit-prediction score of 46% places it in the 99th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-502.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 46% (99th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-502
Affected product: Rubyonrails Rails
Published: 2020-06-19
Last modified: 2026-06-17

Description

A deserialization of untrusted data vulnernerability exists in rails < 5.2.4.3, rails < 6.0.3.1 that can allow an attacker to unmarshal user-provided objects in MemCacheStore and RedisCacheStore potentially resulting in an RCE.

Frequently asked questions

What is CVE-2020-8165?: A deserialization of untrusted data vulnernerability exists in rails < 5.2.4.3, rails < 6.0.3.1 that can allow an attacker to unmarshal user-provided objects in MemCacheStore and RedisCacheStore potentially resulting in an RCE.
How severe is CVE-2020-8165?: CVE-2020-8165 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-2020-8165 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 46% (99th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-8165?: CVE-2020-8165 primarily affects Rubyonrails Rails. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-8165?: 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-2020-8165 published?: CVE-2020-8165 was published on 2020-06-19 and last updated on 2026-06-17.

References

Affected products (6)

cpe:2.3:a:rubyonrails:rails:*:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:*
cpe:2.3:o:opensuse:leap:15.2:*:*:*:*:*:*:*

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