CVE-2021-27362
Description
The WPG plugin before 3.1.0.0 for IrfanView 4.57 has a Read Access Violation on Control Flow starting at WPG!ReadWPG_W+0x0000000000000133, which might allow remote attackers to execute arbitrary code.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected products
2- IrfanView/IrfanViewdescription
Patches
Vulnerability mechanics
Root cause
"Missing bounds validation in WPG.DLL's pixel data write routine allows reading from unallocated or freed memory when processing a crafted WPG file."
Attack vector
An attacker crafts a malicious WPG file that triggers a read access violation when parsed by IrfanView's WPG.DLL plugin. The vulnerability is triggered when the user opens the crafted WPG file in IrfanView. The decompiled code shows that the write routine `sub_7C42E78` computes buffer offsets using attacker-controlled dimensions and bit-depth values without validating that the resulting offset stays within allocated memory, leading to a read from unallocated or freed memory [ref_id=1].
Affected code
The vulnerability resides in the WPG.DLL plugin (version before 3.1.0.0) for IrfanView 4.57. The crash occurs in the function `ReadWPG_W+0x133` (as referenced in the CVE description), which corresponds to the decompiled function `sub_7C42E78` that writes pixel data into a buffer. The caller function `sub_7C4326C` invokes this write routine in a loop without proper bounds checking [ref_id=1].
What the fix does
The advisory does not provide a patch diff. The vendor recommendation is to upgrade to the latest available version of the WPG plugin (3.1.0.0 or later) which patches the security issues [ref_id=1]. No specific fix details are published in the available reference materials.
Preconditions
- inputUser must open a malicious WPG file in IrfanView
- configIrfanView 4.57 with WPG plugin version before 3.1.0.0
Generated on May 25, 2026. Inputs: CWE entries + fix-commit diffs from this CVE's patches. Citations validated against bundle.
References
2- sec-consult.com/vulnerability-lab/advisory/multiple-vulnerabilities-irfanview-wpg/mitrex_refsource_MISC
- www.irfanview.com/plugins.htmmitrex_refsource_MISC
News mentions
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