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Fencer Vulns
critical 10.0

CVE-2021-40426 json

A heap-based buffer overflow vulnerability exists in the sphere.c start_read() functionality of Sound Exchange libsox 14.4.2 and master com…

published 2022-04-14 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-27603

cvss
10.0
version 3.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
2.1%
EPSS 2.1% chance of exploitation in 30 days, percentile 81%
public exploits
0
none known

Summary

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.

Patch / fix

  • sox Debian 13, Debian 12 14.4.2+git20190427-3.1

debian advisories DEBIAN-CVE-2021-40426

  • sox Ubuntu 18.04 LTS 14.4.2-3ubuntu0.18.04.2
  • sox Ubuntu 20.04 LTS 14.4.2+git20190427-2+deb11u1build0.20.04.1
  • sox Ubuntu 22.04 LTS 14.4.2+git20190427-2+deb11u1build0.22.04.1
  • sox Ubuntu Pro 14.04 LTS 14.4.1-3ubuntu1.1+esm2
  • sox Ubuntu Pro 16.04 LTS 14.4.1-5+deb8u4ubuntu0.1+esm1

ubuntu advisories UBUNTU-CVE-2021-40426

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • sox openSUSE Tumbleweed 14.4.2-8.1
  • sox Package Hub 15 SP5, openSUSE Leap 15.5 14.4.2-bp155.3.3.1
  • sox Package Hub 15 SP4, openSUSE Leap 15.4 14.4.2-bp154.2.3.1

opensuse advisories openSUSE-SU-2024:13359-1openSUSE-SU-2023:0329-1openSUSE-SU-2023:0328-1

  • sox Alpine 3.24, Alpine 3.23, Alpine 3.22 +4 more 14.4.2-r10

alpine advisories ALPINE-CVE-2021-40426

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-40426 updated cvss 8.8

sox: heap-based buffer overflow vulnerability exists in the sphere.c start_read() function

  • Red Hat Enterprise Linux 6 sox Red Hat Enterprise Linux 7 sox
    affected: no fix planned “Out of support scope”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
total
Assessed
18 mo ago

Exploit prediction

2.05% chance of exploitation in the next 30 days, higher than 81% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • talosintelligence.com https://talosintelligence.com/vulnerability_reports/TALOS-2021-1434 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.0 10.0 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
NVD 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
NVD 2.0 6.8 AV:N/AC:M/Au:N/C:P/I:P/A:P

Affected products

  • Sound Exchange libsox

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.