CVE-2026-49271
Description
A flaw was found in libheif, a decoder and encoder for HEIF and AVIF file formats. A remote attacker could exploit this vulnerability by providing a specially crafted HEIF file. The uncompressed HEIF decoder's validation of icef compressed-unit offsets can experience an integer wrap-around. This allows the attacker to cause an out-of-bounds heap read, leading to a crash and resulting in a Denial of Service (DoS) for the application using libheif.
Statement
Moderate: This flaw in libheif, which could lead to a denial of service through a crafted HEIF file, does not affect Red Hat products. The vulnerable code responsible for the integer wrap-around in the uncompressed HEIF decoder is not present in Red Hat's supported versions of libheif.
Mitigation
Configure the service to automatically restart on failure to maintain uptime if an exploit triggers a crash.
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart; DoS: Resource Consumption (Memory); DoS: Instability
This weakness can generally lead to undefined behavior and therefore crashes. When the calculated result is used for resource allocation, this weakness can cause too many (or too few) resources to be allocated, possibly enabling crashes if the product requests more resources than can be provided.
Integrity
Technical Impact: Modify Memory
If the value in question is important to data (as opposed to flow), simple data corruption has occurred. Also, if the overflow/wraparound results in other conditions such as buffer overflows, further memory corruption may occur.
Confidentiality,Availability,Access Control
Technical Impact: Execute Unauthorized Code or Commands; Bypass Protection Mechanism
This weakness can sometimes trigger buffer overflows, which can be used to execute arbitrary code. This is usually outside the scope of the product's implicit security policy.
Availability,Other
Technical Impact: Alter Execution Logic; DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU)
If the overflow/wraparound occurs in a loop index variable, this could cause the loop to terminate at the wrong time - too early, too late, or not at all (i.e., infinite loops). With too many iterations, some loops could consume too many resources such as memory, file handles, etc., possibly leading to a crash or other DoS.
Access Control
Technical Impact: Bypass Protection Mechanism
If integer values are used in security-critical decisions, such as calculating quotas or allocation limits, integer overflows can be used to cause an incorrect security decision.
Frequently Asked Questions
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