CVE-2021-3756

Heap overwrite via SOFA header parsing

Published Oct 29, 2021 · Updated Aug 3, 2024

Heap-based buffer overflow in libmysofa before 1.2.1 allows attackers to crash consuming applications via crafted SOFA files. The loudness(), mysofa_check(), and readOHDRHeaderMessageDataLayout() paths process attacker-controlled SOFA header sizes without sufficient heap bounds, allowing writes beyond allocated buffers. An attacker must supply a malicious SOFA file to an application that invokes these library routines; the consequence is process interruption and possible memory corruption.

CVSS severity9.8
Critical
EPSS probability1.07%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap-based buffer overflow in libmysofa before 1.2.1 allows attackers to crash consuming applications via crafted SOFA files. The loudness(), mysofa_check(), and readOHDRHeaderMessageDataLayout() paths process attacker-controlled SOFA header sizes without sufficient heap bounds, allowing writes beyond allocated buffers. An attacker must supply a malicious SOFA file to an application that invokes these library routines; the consequence is process interruption and possible memory corruption.

The record

CVE
CVE-2021-3756
Published
Oct 29, 2021
Updated
Aug 3, 2024
Vendor
Symonics GmbH
Product
libmysofa
Classifications
CWE-122, CWE-787
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 29, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <1.2.1

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Symonics GmbH · libmysofaversion=unspecified <1.2.1

Published CVSS scores

6.2huntr.devCVSS:3.0/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H
7.5NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-122Heap-based Buffer Overflow
CWE-787Out-of-bounds Write

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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