CVE-2021-28835
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 XNView before 2.50, allows local attackers to execute arbitrary code via crafted GEM bitmap 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 XNView image viewer versions before 2.50 allows local attackers to achieve arbitrary code execution when a user opens a specially crafted GEM bitmap file. The vulnerability stems from insufficient bounds checking when parsing the GEM bitmap file format.
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< 2.50CVSS 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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Verify XNView is installedCheck for XNView installation by looking in common install locations (Program Files on Windows, /Applications on Mac, or search for xnview executable in system PATH)Affected if XNView software is present on the system
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Determine installed XNView versionOpen XNView and navigate to Help > About, or right-click the xnview.exe file and select Properties > Details to view the version numberAffected if The displayed version is any version before 2.50 (e.g., 2.49, 2.48, etc.)
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Check for GEM file type associationAttempt to open a known GEM bitmap file (.gem extension) using XNView, or check File > Open dialog for .gem file visibilityAffected if XNView can open and process .gem bitmap files
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Verify GEM parsing functionality is activeAttempt to load a sample .gem file in XNView to confirm the file format parser is functionalAffected if The GEM bitmap file opens without error or crashes the application
A system is affected if XNView version is below 2.50 and the application can parse GEM bitmap files (default behavior in vulnerable versions).
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.
dbcve · scoped2.50
Update XNView to version 2.50 or later to remediate this vulnerability. Users should avoid opening untrusted GEM bitmap files from unknown sources.
XnView 2.50 or later
- Navigate to the official XnView website at www.xnview.com
- Download XnView version 2.50 or later
- Install the downloaded version, replacing the previous installation
- Verify the installation was successful by checking the version number
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation1.0 h
- Testing2.0 h
- Review / QA1.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2021-28835 — 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-2021-28835 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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