CVE-2021-3474Network attack vector

Application interruption via FastHufDecoder shift overflow

Published Mar 30, 2021 · Updated Aug 3, 2024

Integer overflow in OpenEXR 2.4.2 and earlier and 2.5.0 through 2.5.3 allows attackers to interrupt applications via crafted EXR files. FastHufDecoder calculates Huffman code-length scaling factors with a 32-bit left shift, so large code-length differences overflow before conversion to double. Any application or service that decodes attacker-controlled EXR input can suffer a service interrupt; no confidentiality or integrity impact is reported.

CVSS severity5.3
Medium
EPSS probability1.85%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Integer overflow in OpenEXR 2.4.2 and earlier and 2.5.0 through 2.5.3 allows attackers to interrupt applications via crafted EXR files. FastHufDecoder calculates Huffman code-length scaling factors with a 32-bit left shift, so large code-length differences overflow before conversion to double. Any application or service that decodes attacker-controlled EXR input can suffer a service interrupt; no confidentiality or integrity impact is reported.

The record

CVE
CVE-2021-3474
Published
Mar 30, 2021
Updated
Aug 3, 2024
Vendor
Academy Software Foundation
Product
OpenEXR
Classifications
CWE-190, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 30, 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?

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  1. Affected versionversion=OpenEXR 3.0.0-beta

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Academy Software Foundation · OpenEXRversion=OpenEXR 3.0.0-beta

Published CVSS scores

5.3NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
5.0NVDAV:N/AC:L/Au:N/C:N/I:N/A:P
5.3SUSECVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-190Integer Overflow or Wraparound
T1499.004Application or System Exploitation

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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