CVE-2020-36323

In the standard library in Rust before 1.52.0, there is an optimization for joining strings that can cause uninitialized bytes to be exposed (or the program to crash) if the borrowed string changes after its length is checked.

Published: 2021-04-14 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-36323 is rated Moderate Risk (60.2/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.01%). Review affected assets and schedule remediation.

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

Exploit prediction scoring system (EPSS) score for CVE-2020-36323

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 2026-05-29 0.71% 1.01% +0.30%
2 2025-11-21 1.01% 0.71% -0.30%
3 2025-11-18 — 1.01% —

Full EPSS history (18 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-36323

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.2 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/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:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 4.2 [email protected]
6.4 2.0 MEDIUM
AV:N/AC:L/Au:N/C:P/I:N/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:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 4.9 [email protected]

Weakness enumeration for CVE-2020-36323

OS Trackers for CVE-2020-36323

vendor priority summary link
alpine high CVE-2020-36323: 1 source package rows (rust); 20 state rows across 8 repos (3.17-community, 3.18-community, 3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-community, edge-main); fixed 8, open 12. https://security.alpinelinux.org/vuln/CVE-2020-36323
debian not yet assigned CVE-2020-36323 not yet assigned priority: Debian including 1 source packages (rustc), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 4, open 1. https://security-tracker.debian.org/tracker/CVE-2020-36323
redhat medium — https://access.redhat.com/security/cve/CVE-2020-36323
suse medium CVE-2020-36323 severity moderate: SUSE including 46 source package names (cargo, cargo-1.52.1-1.module+el8.4.0+11282+0729bac9, …), 151 product×package rows across 23 product lines (SUSE CaaS Platform 4.0, SUSE Enterprise Storage 6, … (23 product lines)): Known Not Affected 137, Fixed 14. https://www.suse.com/security/cve/CVE-2020-36323/
ubuntu medium CVE-2020-36323 medium priority: Ubuntu including 1 source packages (rustc), 16 status rows across 16 suites (bionic, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): ignored 4, not-affected 4, DNE 3, needed 2, released 2, needs-triage 1. https://ubuntu.com/security/CVE-2020-36323

Affected software / configurations for CVE-2020-36323

Vendor Product Version Raw CPE
rust-lang rust < 1.52.0 cpe:2.3:a:rust-lang:rust:*:*:*:*:*:*:*:*
fedoraproject fedora 32 cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*
fedoraproject fedora 33 cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
fedoraproject fedora 34 cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*

References for CVE-2020-36323

cvelogic Threat Intelligence