CVE-2020-28928

In musl libc through 1.2.1, wcsnrtombs mishandles particular combinations of destination buffer size and source character limit, as demonstrated by an invalid write access (buffer overflow).

Published: 2020-11-24 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-28928 is rated Low Risk (38.7/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.64%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

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-2020-28928

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 2026-06-15 0.04% 0.64% +0.60%
2 2025-11-21 0.11% 0.04% -0.07%
3 2025-11-18 — 0.11% —

Full EPSS history (13 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-28928

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.5 3.1 MEDIUM
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
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:L)
A normal user session is enough; they don’t have to be admin.
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:N)
Doesn’t really leak secrets in a meaningful way.
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.
 1.8 3.6 [email protected]
2.1 2.0 LOW
AV:L/AC:L/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:L)
Requires local access to the target system.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 3.9 2.9 [email protected]

Weakness enumeration for CVE-2020-28928

OS Trackers for CVE-2020-28928

vendor priority summary link
alpine medium CVE-2020-28928: 1 source package rows (musl); 20 state rows across 10 repos (3.10-main, 3.11-main, 3.12-main, 3.17-main, 3.18-main, 3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 10, open 10. https://security.alpinelinux.org/vuln/CVE-2020-28928
debian not yet assigned CVE-2020-28928 not yet assigned priority: Debian including 1 source packages (musl), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2020-28928
ubuntu medium CVE-2020-28928 medium priority: Ubuntu including 1 source packages (musl), 15 status rows across 15 suites (bionic, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, trusty, upstream, xenial): not-affected 7, released 4, ignored 3, needs-triage 1. https://ubuntu.com/security/CVE-2020-28928

Affected software / configurations for CVE-2020-28928

Vendor Product Version Raw CPE
musl-libc musl <= 1.2.1 cpe:2.3:a:musl-libc:musl:*:*:*:*:*:*:*:*
debian debian_linux 9.0 cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
fedoraproject fedora 33 cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
fedoraproject fedora 34 cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
oracle graalvm 20.3.2 cpe:2.3:a:oracle:graalvm:20.3.2:*:*:*:enterprise:*:*:*
oracle graalvm 21.1.0 cpe:2.3:a:oracle:graalvm:21.1.0:*:*:*:enterprise:*:*:*

References for CVE-2020-28928

URL Tags
http://www.openwall.com/lists/oss-security/2020/11/20/4 Mailing List Third Party Advisory
https://lists.apache.org/thread.html/r2134abfe847bea7795f0e53756d10a47e6643f35ab8169df8b8a9eb1%40%3Cnotifications.apisix.apache.org%3E
https://lists.apache.org/thread.html/r90b60cf49348e515257b4950900c1bd3ab95a960cf2469d919c7264e%40%3Cnotifications.apisix.apache.org%3E
https://lists.apache.org/thread.html/ra63e8dc5137d952afc55dbbfa63be83304ecf842d1eab1ff3ebb29e2%40%3Cnotifications.apisix.apache.org%3E
https://lists.debian.org/debian-lts-announce/2020/11/msg00050.html Mailing List Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LKQ3RVSMVZNZNO4D65W2CZZ4DMYFZN2Q/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UW27QVY7ERPTSGKS4KAWE5TU7EJWHKVQ/
https://musl.libc.org/releases.html Release Notes Vendor Advisory
https://www.oracle.com//security-alerts/cpujul2021.html Patch Third Party Advisory
https://www.oracle.com/security-alerts/cpuoct2021.html Patch Third Party Advisory
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