CVE-2021-3756: libmysofa is vulnerable to Heap-based Buffer Overflow

Q: How do I fix CVE-2021-3756?

libmysofa: upgrade to 1.2.1; fedora: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2021-3756 being exploited?

CVE-2021-3756 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2021-3756 affect?

CVE-2021-3756 affects libmysofa, fedora. Severity is critical (CVSS 9.8). libmysofa is vulnerable to Heap-based Buffer Overflow

Q: How urgent is CVE-2021-3756?

Priority 60/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

This week

CRITICAL 9.8REMOTEUPGRADEMITIGATE

CVE-2021-3756 is a critical-severity flaw (CVSS 9.8) affecting libmysofa, fedora. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

libmysofa is vulnerable to Heap-based Buffer Overflow

Why this priority

Critical severity
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.1% (top 35%)
CISA exploited list	No
Weakness	CWE-122, CWE-787
Published	2021-10-29
Last modified	2026-06-17

Publisher (CNA): huntr.dev · Vendor: fedoraproject · symonics

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

Am I affected?

Timeline

2021-10-29 16:15 UTCPublished CVE record published
2026-06-17 04:05 UTCUpdated Record last modified

symonics libmysofa UPGRADE

Affected: < 1.2.1

Fixed in: 1.2.1

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy libmysofa || rpm -q libmysofa || libmysofa --version

2. UPGRADE to 1.2.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade libmysofa

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade libmysofa

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

fedoraproject fedora MITIGATE

Affected: 34 · 35

Fixed in: no fixed release known

Safe to downgrade to: a release before 34

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

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-2021-3756?

libmysofa: upgrade to 1.2.1; fedora: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-3756 being exploited?

CVE-2021-3756 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-2021-3756 affect?

CVE-2021-3756 affects libmysofa, fedora. Severity is critical (CVSS 9.8). libmysofa is vulnerable to Heap-based Buffer Overflow

How urgent is CVE-2021-3756?

Priority 60/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

Related CVEs

CVE-2020-36152 HIGH 8.8 UPGRADE MITIGATE Buffer overflow in readDataVar in hdf/dataobject.c in Symonics libmysofa 0.5 - 1.1 allows attackers to execute
CVE-2020-36151 MEDIUM 6.5 UPGRADE MITIGATE Incorrect handling of input data in mysofa_resampler_reset_mem function in the libmysofa library 0.5 - 1.1 wil
CVE-2020-36150 MEDIUM 6.5 UPGRADE MITIGATE Incorrect handling of input data in loudness function in the libmysofa library 0.5 - 1.1 will lead to heap buf
CVE-2020-36149 MEDIUM 6.5 UPGRADE MITIGATE Incorrect handling of input data in changeAttribute function in the libmysofa library 0.5 - 1.1 will lead to N
CVE-2020-36148 MEDIUM 6.5 UPGRADE MITIGATE Incorrect handling of input data in verifyAttribute function in the libmysofa library 0.5 - 1.1 will lead to N

References

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