CVE-2026-25884: Exiv2 Buffer Overflow Vulnerability

CVE-2026-25884 Overview

CVE-2026-25884 is an out-of-bounds read vulnerability affecting Exiv2, a widely-used C++ library and command-line utility for reading, writing, deleting, and modifying Exif, IPTC, XMP, and ICC image metadata. The vulnerability exists in the CRW image parser component, where improper bounds checking can allow attackers to read memory beyond allocated buffers when processing specially crafted Canon RAW (CRW) image files.

Critical Impact

Attackers can craft malicious CRW image files that trigger out-of-bounds memory reads, potentially leading to information disclosure or application instability when processing untrusted image metadata.

Affected Products

• Exiv2 versions prior to 0.28.8
• Applications and services that integrate the Exiv2 library for metadata processing
• Systems processing untrusted CRW image files using vulnerable Exiv2 versions

Discovery Timeline

• 2026-03-02 - CVE-2026-25884 published to NVD
• 2026-03-05 - Last updated in NVD database

Technical Details for CVE-2026-25884

Vulnerability Analysis

This vulnerability is classified as CWE-125 (Out-of-Bounds Read) and affects the CRW image parser within the Exiv2 library. The flaw stems from improper handling of string data extracted from CIFF (Camera Image File Format) components when parsing Canon RAW image files.

In the vulnerable code path, the CrwMap::decode0x0805 function constructs a string from raw image data without properly constraining the string length to the actual component size. This allows memory reads beyond the intended buffer boundaries when processing malformed or malicious CRW files.

The vulnerability is network-exploitable, as malicious images can be delivered through web applications, email attachments, or any workflow that processes user-supplied image files. While the severity is rated LOW due to the limited impact (primarily information disclosure), the vulnerability affects any application that uses Exiv2 to process untrusted image metadata.

Root Cause

The root cause lies in the src/crwimage_int.cpp file within the CrwMap::decode0x0805 function. The vulnerable code creates a std::string object directly from a raw pointer without specifying the expected length, relying instead on null-termination. If the CIFF component data lacks proper null-termination or contains embedded null characters at unexpected positions, the string constructor can read beyond the allocated buffer.

Attack Vector

An attacker can exploit this vulnerability by crafting a malicious CRW image file containing a specially designed CIFF component (specifically the 0x0805 component used for image comments). When a vulnerable application processes this file using Exiv2, the out-of-bounds read is triggered, potentially leaking sensitive memory contents or causing application instability.

The attack vector is network-based, requiring no authentication or user interaction beyond the target application processing the malicious image file. This makes the vulnerability particularly relevant for web applications, image galleries, and automated image processing pipelines that handle untrusted user uploads.

// Security patch - src/crwimage_int.cpp
// Source: https://github.com/Exiv2/exiv2/commit/cbba4d206512fe63e12d164fdd1881562f072a9d

void CrwMap::decode0x0805(const CiffComponent& ciffComponent, const CrwMapping* /*pCrwMapping*/, Image& image,
                          ByteOrder /*byteOrder*/) {
-  std::string s(reinterpret_cast<const char*>(ciffComponent.pData()));
+  auto s = std::string(reinterpret_cast<const char*>(ciffComponent.pData()), ciffComponent.size());
   image.setComment(s);
}  // CrwMap::decode0x0805

The fix explicitly specifies the size parameter when constructing the string, ensuring that memory reads are bounded by the actual component size rather than relying on null-termination.

Detection Methods for CVE-2026-25884

Indicators of Compromise

• Unusual crashes or segmentation faults in applications processing CRW image files
• Unexpected memory access patterns when parsing Canon RAW images
• Application logs showing errors related to Exiv2 metadata extraction from CRW files
• Anomalous CRW files with malformed CIFF component structures

Detection Strategies

• Monitor for applications using Exiv2 library versions prior to 0.28.8
• Implement file integrity monitoring for image processing workflows
• Deploy runtime memory protection tools (ASAN, Valgrind) in development and testing environments
• Scan incoming CRW files for anomalous CIFF component sizes or structures

Monitoring Recommendations

• Enable verbose logging for image metadata processing operations
• Monitor system memory access patterns during image file processing
• Implement automated vulnerability scanning for Exiv2 library dependencies
• Track application stability metrics for services processing user-uploaded images

How to Mitigate CVE-2026-25884

Immediate Actions Required

• Upgrade Exiv2 to version 0.28.8 or later immediately
• Audit all applications and services that depend on the Exiv2 library
• Temporarily disable CRW file processing if immediate patching is not feasible
• Implement input validation to reject suspicious CRW files pending the update

Patch Information

The vulnerability has been patched in Exiv2 version 0.28.8. The fix ensures proper bounds checking when constructing strings from CIFF component data by explicitly passing the component size to the string constructor.

For detailed patch information, refer to:

• GitHub Security Advisory GHSA-9mxq-4j5g-5wrp
• Pull Request #3462
• Commit cbba4d206512fe63e12d164fdd1881562f072a9d

Workarounds

• Block or quarantine CRW files at the network perimeter until systems are patched
• Implement sandboxing for image processing operations to limit potential impact
• Deploy Web Application Firewalls (WAF) with rules to inspect uploaded image files
• Use container isolation for services that process untrusted image metadata

# Configuration example - Check and upgrade Exiv2 version
# Check current Exiv2 version
exiv2 --version

# On Debian/Ubuntu systems
apt update && apt install exiv2

# On Red Hat/CentOS systems
yum update exiv2

# Verify the updated version is 0.28.8 or later
exiv2 --version | grep -E "^exiv2 0\.28\.[89]|^exiv2 0\.29"