CVE-2020-21528

Exp

A Segmentation Fault issue discovered in in ieee_segment function in outieee.c in nasm 2.14.03 and 2.15 allows remote attackers to cause a denial of service via crafted assembly file.

Published: 2023-08-22 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-21528 is rated Exploit Available (59.7/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 0.48%). 1 public exploit reference(s) are indexed (Exploit-DB). 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-2020-21528

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

Exploit prediction scoring system (EPSS) score for CVE-2020-21528

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 2026-02-16 0.37% 0.48% +0.11%
2 2025-11-21 0.12% 0.37% +0.25%
3 2025-11-18 — 0.12% —

Full EPSS history (8 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-21528

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:N/UI:R/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:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
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]

Weakness enumeration for CVE-2020-21528

OS Trackers for CVE-2020-21528

vendor priority summary link
debian unimportant CVE-2020-21528 unimportant priority: Debian including 1 source packages (nasm), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 4, open 1. https://security-tracker.debian.org/tracker/CVE-2020-21528
gentoo high CVE-2020-21528: 1 GLSA(s) (202312-09), 1 atom(s) (dev-lang/nasm); latest impact high. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2020-21528
redhat low — https://access.redhat.com/security/cve/CVE-2020-21528
suse low CVE-2020-21528 severity low: SUSE including 1 source package names (nasm), 17 product×package rows across 17 product lines (SUSE CaaS Platform 4.0, SUSE Enterprise Storage 7.1, … (17 product lines)): Will Not Fix 17. https://www.suse.com/security/cve/CVE-2020-21528/
ubuntu medium CVE-2020-21528 medium priority: Ubuntu including 1 source packages (nasm), 12 status rows across 12 suites (bionic, focal, jammy, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): not-affected 5, ignored 4, needed 2, needs-triage 1. https://ubuntu.com/security/CVE-2020-21528

Affected software / configurations for CVE-2020-21528

Vendor Product Version Raw CPE
nasm netwide_assembler 2.14.03 cpe:2.3:a:nasm:netwide_assembler:2.14.03:rc2:*:*:*:*:*:*
nasm netwide_assembler 2.15 cpe:2.3:a:nasm:netwide_assembler:2.15:*:*:*:*:*:*:*

References for CVE-2020-21528

cvelogic Threat Intelligence