CVE-2021-40426

Exp

A heap-based buffer overflow vulnerability exists in the sphere.c start_read() functionality of Sound Exchange libsox 14.4.2 and master commit 42b3557e. A specially-crafted file can lead to a heap buffer overflow. An attacker can provide a malicious file to trigger this vulnerability.

Published: 2022-04-14 Last update: 2025-06-24 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-40426 is rated High Exploit Risk (74.1/100): CVSS High severity, with medium exploitation likelihood (EPSS 0.55%). 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-2021-40426

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

Exploit prediction scoring system (EPSS) score for CVE-2021-40426

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 2026-05-27 0.54% 0.55% +0.01%
2 2026-04-11 0.16% 0.54% +0.38%
3 2026-03-23 — 0.16% —

Full EPSS history (20 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-40426

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.8 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/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: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: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.
 2.8 5.9 [email protected]
10.0 3.0 CRITICAL
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/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:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
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 6.0 [email protected]
6.8 2.0 MEDIUM
AV:N/AC:M/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:M)
Exploitation needs some favorable conditions, but not exceptional ones.
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.
 8.6 6.4 [email protected]

Weakness enumeration for CVE-2021-40426

OS Trackers for CVE-2021-40426

vendor priority summary link
alpine — CVE-2021-40426: 1 source package rows (sox); 6 state rows across 6 repos (3.18-community, 3.19-community, 3.20-community, 3.21-community, 3.22-community, edge-community); fixed 6, open 0. https://security.alpinelinux.org/vuln/CVE-2021-40426
debian not yet assigned CVE-2021-40426 not yet assigned priority: Debian including 1 source packages (sox), 3 status rows across 3 suites (bookworm, bullseye, trixie): resolved 3. https://security-tracker.debian.org/tracker/CVE-2021-40426
redhat medium — https://access.redhat.com/security/cve/CVE-2021-40426
ubuntu medium CVE-2021-40426 medium priority: Ubuntu including 1 source packages (sox), 13 status rows across 13 suites (bionic, focal, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, trusty, upstream, xenial): released 6, ignored 4, not-affected 2, needs-triage 1. https://ubuntu.com/security/CVE-2021-40426

Affected software / configurations for CVE-2021-40426

Vendor Product Version Raw CPE
sound_exchange_project sound_exchange 14.4.2 cpe:2.3:a:sound_exchange_project:sound_exchange:14.4.2:*:*:*:*:*:*:*

References for CVE-2021-40426

cvelogic Threat Intelligence