CVE-2020-8165

Exp

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.

Published: 2020-06-19 Last update: 2025-05-09 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-8165 is rated High Exploit Risk (94.1/100): CVSS Critical severity, with high exploitation likelihood (EPSS 90.13%, 100th percentile). 1 public exploit reference(s) are indexed (Exploit-DB). EPSS rose +7.07% over the last day, indicating growing attacker interest. Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2020-8165

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2020-8165

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-03-04 83.06% 90.13% +7.07%
2 2026-03-01 90.13% 83.06% -7.07%
3 2026-02-04 — 90.13% —

Full EPSS history (36 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-8165

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.8 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 5.9 [email protected]
7.5 2.0 HIGH
AV:N/AC:L/Au:N/C:P/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 6.4 [email protected]

Weakness enumeration for CVE-2020-8165

GitHub Security Advisory for CVE-2020-8165

GHSA-2p68-f74v-9wc6 · Severity: critical · Ecosystem: rubygems — ActiveSupport potentially unintended unmarshalling of user-provided objects in MemCacheStore and RedisCacheStore

OS Trackers for CVE-2020-8165

vendor priority summary link
debian not yet assigned CVE-2020-8165 not yet assigned priority: Debian including 1 source packages (rails), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2020-8165
redhat high — https://access.redhat.com/security/cve/CVE-2020-8165
suse critical — https://www.suse.com/security/cve/CVE-2020-8165/
ubuntu medium CVE-2020-8165 medium priority: Ubuntu including 7 source packages (rails, rails-4.0, …), 119 status rows across 17 suites (bionic, eoan, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 97, not-affected 11, needs-triage 10, ignored 1. https://ubuntu.com/security/CVE-2020-8165

Affected software / configurations for CVE-2020-8165

Vendor Product Version Raw CPE
rubyonrails rails < 5.2.4.3 cpe:2.3:a:rubyonrails:rails:*:*:*:*:*:*:*:*
rubyonrails rails >= 6.0.0, < 6.0.3.1 cpe:2.3:a:rubyonrails:rails:*:*:*:*:*:*:*:*
debian debian_linux 8.0 cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*
debian debian_linux 9.0 cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
debian debian_linux 10.0 cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
opensuse leap 15.1 cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:*
opensuse leap 15.2 cpe:2.3:o:opensuse:leap:15.2:*:*:*:*:*:*:*

References for CVE-2020-8165

URL Tags
http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00031.html Mailing List Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00034.html Mailing List Third Party Advisory
https://groups.google.com/g/rubyonrails-security/c/bv6fW4S0Y1c Mailing List Patch Third Party Advisory
https://hackerone.com/reports/413388 Exploit Patch Third Party Advisory
https://lists.debian.org/debian-lts-announce/2020/06/msg00022.html Mailing List Third Party Advisory
https://lists.debian.org/debian-lts-announce/2020/07/msg00013.html Mailing List Third Party Advisory
https://weblog.rubyonrails.org/2020/5/18/Rails-5-2-4-3-and-6-0-3-1-have-been-released/ Vendor Advisory
https://www.debian.org/security/2020/dsa-4766 Third Party Advisory
https://security.netapp.com/advisory/ntap-20250509-0002/
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