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NVD / CVE Program· CNA talos

CVE-2021-40426: A heap-based buffer overflow vulnerability exists in the sphere.c start_read() functionality of Sound Exchange libsox 14.4.2 and master comm

Noroxi assessment

Priority: Monitor (action score 36/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 2% (FIRST EPSS); higher than 81.2% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. A user must open a link or visit a page. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: sox (Debian:10) 14.4.2+git20190427-1+deb10u1; sox (Debian:11) 14.4.2+git20190427-2+deb11u1; sox (Debian:12) 14.4.2+git20190427-3.1.

Low priority for now. Upgrade to sox (Debian:10) 14.4.2+git20190427-1+deb10u1; sox (Debian:11) 14.4.2+git20190427-2+deb11u1; sox (Debian:12) 14.4.2+git20190427-3.1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

HighCVSS 8.8 · v3.1—No exploit Fix available
Published
Apr 14, 2022
Updated
Jun 17, 2026
EPSS
2.0% · 81th percentile

Report tools

JSON

Action score

36

Monitor

Low priority for now.

CVSS
35 / 40 · 8.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
1 / 30 · 2.0%

CISA SSVC decision

Exploitation
proof of concept
Automatable
yes
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
8.8
CNA · talos
10.0
1.2 point gap

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2021-40426

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
sound exchange projectsound exchange

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • sound exchange project sound exchange14.4.2

Versions reported by the vendor

Affected version ranges reported by the assigning authority (talos). Independent of NVD's CPE analysis and usually ahead of it.

  • Sound Exchange libsox

    • 14.4.2, master commit 42b3557eaffected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:10soxbefore 14.4.2+git20190427-1+deb10u114.4.2+git20190427-1+deb10u1
Debian:11soxbefore 14.4.2+git20190427-2+deb11u114.4.2+git20190427-2+deb11u1
Debian:12soxbefore 14.4.2+git20190427-3.114.4.2+git20190427-3.1
openSUSE:Leap 15.4soxbefore 14.4.2-bp154.2.3.114.4.2-bp154.2.3.1
openSUSE:Leap 15.5soxbefore 14.4.2-bp155.3.3.114.4.2-bp155.3.3.1
openSUSE:Tumbleweedsoxbefore 14.4.2-8.114.4.2-8.1
SUSE:Package Hub 15 SP4soxbefore 14.4.2-bp154.2.3.114.4.2-bp154.2.3.1
SUSE:Package Hub 15 SP5soxbefore 14.4.2-bp155.3.3.114.4.2-bp155.3.3.1

Same product

sound exchange project: all records

Other highest-scoring records for the same primary product.

  • CVE-2021-3643A flaw was found in sox 14.4.1.
    36Monitor
  • CVE-2017-18189In the startread function in xa.c in Sound eXchange (SoX) through 14.4.2, a corrupt header specifying zero channels triggers an infinite loo
    32Monitor
  • CVE-2014-8145Multiple heap-based buffer overflows in Sound eXchange (SoX) 14.4.1 and earlier allow remote attackers to have unspecified impact via a craf
    32Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2019-13590Jul 14, 2019 · An issue was discovered in libsox.a in SoX 14.4.2.
    22Monitor
  • ← EarlierCVE-2019-1010004Jul 14, 2019 · SoX - Sound eXchange 14.4.2 and earlier is affected by: Out-of-bounds Read.
    22Monitor
  • Later →CVE-2022-31650May 25, 2022 · In SoX 14.4.2, there is a floating-point exception in lsx_aiffstartwrite in aiff.c in libsox.a.
    22Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
debian:sox14.4.2+git20190427-3.1 · Debian:12Package registry (OSV)
opensuse:sox14.4.2-bp154.2.3.1 · openSUSE:Leap 15.4Package registry (OSV)
suse:sox14.4.2-bp154.2.3.1 · SUSE:Package Hub 15 SP4Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • A user must open a link or visit a page.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-122 · Heap-based Buffer Overflow

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (2 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records