CVE-2021-40426: A heap-based buffer overflow vulnerability exists in the sphere.c start_read() functionality of Sound Exchange

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HIGH 8.8DOWNGRADE

CVE-2021-40426 is a high-severity flaw (CVSS 8.8) affecting sound exchange. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

High severity
Public exploit reference

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	8.8 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	2.1% (top 19%)
CISA exploited list	No
Weakness	CWE-122, CWE-787
Published	2022-04-14
Last modified	2026-06-17

Publisher (CNA): Talos · Vendor: sound exchange project

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2022-04-14 20:15 UTCPublished CVE record published
2026-06-17 04:06 UTCUpdated Record last modified

sound exchange project sound exchange DOWNGRADE

Affected: 14.4.2

Fixed in: no fixed release known

Safe to downgrade to: a release before 14.4.2

1. Check installed version

apt-cache policy sound-exchange || rpm -q sound-exchange || sound-exchange --version

2. No fixed release: DOWNGRADE to a release before 14.4.2 (Debian / Ubuntu)

apt-cache madison sound-exchange sudo apt install sound-exchange=<VERSION_BEFORE_14.4.2> sudo apt-mark hold sound-exchange

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list sound-exchange sudo dnf downgrade sound-exchange-<VERSION_BEFORE_14.4.2> sudo dnf versionlock add sound-exchange

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-40426?

sound exchange: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-40426 being exploited?

CVE-2021-40426 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-40426 affect?

CVE-2021-40426 affects sound exchange. Severity is high (CVSS 8.8). 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

How urgent is CVE-2021-40426?

Priority 56/100. High severity; Public exploit reference

Related CVEs

CVE-2023-34432 HIGH 7.8 UPGRADE DOWNGRADE A heap buffer overflow vulnerability was found in sox, in the lsx_readbuf function at sox/src/formats_i.c:98:1
CVE-2023-34318 HIGH 7.8 DOWNGRADE DOWNGRADE A heap buffer overflow vulnerability was found in sox, in the startread function at sox/src/hcom.c:160:41
CVE-2023-32627 MEDIUM 6.2 DOWNGRADE DOWNGRADE A floating point exception vulnerability was found in sox, in the read_samples function at sox/src/voc.c:334:1
CVE-2023-26590 MEDIUM 6.2 DOWNGRADE DOWNGRADE A floating point exception vulnerability was found in sox, in the lsx_aiffstartwrite function at sox/src/aiff.
CVE-2022-31651 MEDIUM 5.5 DOWNGRADE In SoX 14.4.2, there is an assertion failure in rate_init in rate.c in libsox.a.

References

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