CVE-2026-59274 in Integration
Summary
by MITRE • 08/27/2026
The UnZipTransformer does not limit decompressed entry size or entry count when processing archives. Consequently, an attacker can send a zip archive that can exhaust JVM heap memory, causing a denial-of-service outage. Spring Integration 7.1.0 Spring Integration 7.0.0 - 7.0.5 Spring Integration 6.5.0 - 6.5.10 Spring Integration 6.4.0 - 6.4.12
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Analysis
by VulDB Data Team • 08/27/2026
The UnZipTransformer component within the Spring Integration framework contains a critical resource management flaw that allows for denial-of-service attacks through zip bomb exploitation. This vulnerability stems from the absence of safeguards to limit either the size of individual decompressed entries or the total number of entries processed during archive extraction. In standard secure implementations, such transformers typically enforce strict limits on uncompressed data volume and entry counts to prevent malicious actors from abusing the resource-intensive nature of decompression operations. Without these constraints, the component blindly processes every file contained within a submitted zip archive, allocating memory proportional to the expanded content without verifying whether this allocation is reasonable or sustainable for the running application environment.
An attacker can exploit this weakness by crafting a specially designed zip archive that contains either numerous small files with high compression ratios or a single large file compressed using algorithms like deflate in a way that expands significantly when decompressed. This technique, commonly referred to as a zip bomb, relies on the disparity between compressed and uncompressed sizes. When such an archive is submitted to the vulnerable UnZipTransformer, the system attempts to allocate heap memory for all extracted entries simultaneously or sequentially without bounds checking. As the JVM allocates more and more memory to hold these decompressed payloads, it rapidly consumes available heap space, leading to a java.lang.OutOfMemoryError exception. This condition effectively halts normal application processing capabilities, resulting in a complete denial of service for users attempting to interact with the affected Spring Integration endpoints or message channels that utilize this transformer.
The operational impact of this vulnerability is severe, as it directly compromises the availability pillar of the CIA triad. Since the attack targets JVM heap memory, it can cause not only the specific application instance handling the malicious request to crash but potentially destabilize other applications running on the same host if they share resources or monitoring thresholds are triggered by excessive garbage collection pauses preceding an out-of-memory event. The vulnerability affects multiple versions of Spring Integration, specifically 7.1.0 and earlier in that branch, as well as all releases from 6.4.0 through 6.5.10 and the initial release of the 7.0.x line up to version 7.0.5. This broad scope indicates a systemic design oversight across several major maintenance lines rather than an isolated regression in a single patch cycle, necessitating careful version auditing for organizations relying on these frameworks for message transformation workflows involving untrusted zip inputs.
From a classification perspective, this vulnerability aligns with CWE-400, which describes Uncontrolled Resource Consumption, and more specifically CWE-770, Allocation of Resources Without Limits or Throttling. In the context of adversary tactics, this flaw facilitates resource exhaustion attacks that can be categorized under MITRE ATT&CK technique T1496, Host-Based Denial of Service. Attackers do not need to execute arbitrary code or gain unauthorized access to exploit this issue; simply sending a malformed payload through an exposed endpoint is sufficient to degrade service quality or cause total outage. This makes it particularly dangerous in public-facing applications where input validation and size constraints are often overlooked for convenience during initial development phases.
Mitigation strategies must focus on implementing strict resource limits within the transformation pipeline. Developers should configure the UnZipTransformer with explicit maximum entry count thresholds and maximum uncompressed data size limits before processing any incoming archives. If possible, upgrading to a patched version of Spring Integration that includes these safeguards is the primary remediation path. For environments where immediate patching is not feasible, implementing a custom wrapper or pre-processing step that validates zip file metadata such as total compressed size, number of entries, and maximum individual entry sizes can provide an essential layer of defense. Additionally, tuning JVM heap parameters to include tighter memory limits for specific application contexts may help contain the blast radius of an attack, although this is a compensatory control rather than a fix for the underlying architectural flaw. Regular security assessments should verify that all external-facing components performing file transformations enforce these resource constraints consistently across all supported versions in use.