CVE-2021-20300

Service interrupt via Huffman bit-count overflow

Published Mar 4, 2022 · Updated Aug 3, 2024

Integer overflow in OpenEXR before 2.5.4 allows context-dependent attackers to interrupt applications by supplying a crafted EXR file. In hufUncompress, adding 7 to the file-derived nBits value in integer arithmetic wraps before widening, letting the compressed-buffer length check accept insufficient data. The file must be processed by an application linked to the library; the documented consequence is availability loss without data disclosure or modification.

CVSS severity5.5
Medium
EPSS probability0.89%
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 before 2.5.4 allows context-dependent attackers to interrupt applications by supplying a crafted EXR file. In hufUncompress, adding 7 to the file-derived nBits value in integer arithmetic wraps before widening, letting the compressed-buffer length check accept insufficient data. The file must be processed by an application linked to the library; the documented consequence is availability loss without data disclosure or modification.

The record

CVE
CVE-2021-20300
Published
Mar 4, 2022
Updated
Aug 3, 2024
Vendor
Academy Software Foundation
Product
OpenEXR
Classifications
CWE-190, T1499.004
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 4, 2022CVE 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=Fixed in v2.5.4 and beyond.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Academy Software Foundation · OpenEXRversion=Fixed in v2.5.4 and beyond.

Published CVSS scores

5.5GitLab Advisory DatabaseCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/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-190Integer Overflow or Wraparound
T1499.004Endpoint Denial of Service: Application 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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