How severe is CVE-2021-3756?

CVE-2021-3756 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-3756 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (60th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-3756?

CVE-2021-3756 primarily affects Symonics Libmysofa. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-3756?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2021-3756 published?

CVE-2021-3756 was published on 2021-10-29 and last updated on 2026-06-17.

CVE-2021-3756

CVE-2021-3756 is a critical-severity vulnerability in Symonics Libmysofa with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-787.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 1% (60th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-787
Affected product: Symonics Libmysofa
Published: 2021-10-29
Last modified: 2026-06-17

Description

libmysofa is vulnerable to Heap-based Buffer Overflow

Frequently asked questions

What is CVE-2021-3756?: libmysofa is vulnerable to Heap-based Buffer Overflow
How severe is CVE-2021-3756?: CVE-2021-3756 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-3756 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (60th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-3756?: CVE-2021-3756 primarily affects Symonics Libmysofa. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-3756?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-3756 published?: CVE-2021-3756 was published on 2021-10-29 and last updated on 2026-06-17.

References

Affected products (3)

cpe:2.3:a:symonics:libmysofa:*:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*

More vulnerabilities in Symonics Libmysofa

CVE-2019-16093 — Critical (CVSS 9.8): Symonics libmysofa 0.7 has an invalid write in readOHDRHeaderMessageDataLayout in hdf/dataobject.c.
CVE-2019-16092 — Critical (CVSS 9.8): Symonics libmysofa 0.7 has a NULL pointer dereference in getHrtf in hrtf/reader.c.
CVE-2019-10672 — Critical (CVSS 9.8): treeRead in hdf/btree.c in libmysofa before 0.7 does not properly validate multiplications and additions.
CVE-2020-36152 — High (CVSS 8.8): Buffer overflow in readDataVar in hdf/dataobject.c in Symonics libmysofa 0.5 - 1.1 allows attackers to execute…
CVE-2020-6860 — High (CVSS 8.8): libmysofa 0.9.1 has a stack-based buffer overflow in readDataVar in hdf/dataobject.c during the reading of a header…
CVE-2019-20063 — High (CVSS 8.8): hdf/dataobject.c in libmysofa before 0.8 has an uninitialized use of memory, as demonstrated by mysofa2json.

All CVEs affecting Symonics Libmysofa →

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