CVE-2020-21426
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedBuffer Overflow vulnerability in function C_IStream::read in PluginEXR.cpp in FreeImage 3.18.0 allows remote attackers to run arbitrary code and cause other impacts via crafted image file.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceBuffer overflow vulnerability in FreeImage 3.18.0's C_IStream::read function in PluginEXR.cpp when parsing crafted EXR image files. The lack of proper bounds checking during image stream reading allows overflowing the allocated buffer, enabling arbitrary code execution when a malicious EXR file is processed.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data= 3.18.0CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Local
- Complexity
- Low
- Privileges
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify FreeImage versionCheck the installed FreeImage library version by examining the library file properties, header files, or running a version query command specific to the FreeImage build in useAffected if Version is exactly 3.18.0
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Locate PluginEXR componentSearch for PluginEXR.cpp or the compiled EXR plugin module within the FreeImage installation directory or source treeAffected if PluginEXR.cpp source file or compiled EXR plugin exists in the FreeImage installation
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Verify EXR support is enabledConfirm that FreeImage was compiled with EXR format support enabled, typically indicated by the presence of the EXR plugin or loadable moduleAffected if EXR format support is compiled into or loaded by FreeImage
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Determine if EXR file processing is possibleCheck if the system has the capability to process EXR image files through FreeImage, such as by listing supported formats or testing EXR loading functionalityAffected if EXR image files can be loaded or processed by the FreeImage installation
User is affected if FreeImage version is exactly 3.18.0 and the EXR plugin with the vulnerable C_IStream::read function is present and capable of processing EXR files on the system.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataUpdate FreeImage to the latest patched version if available; otherwise, implement strict bounds checking in C_IStream::read, validate EXR file headers before processing, and consider sandboxing image processing operations to limit impact of potential exploitation.
- Consultation3.0 h
- Implementation6.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,224.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-21426 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2020-21426 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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