CVE-2026-53941 in Inspektor Gadget
Summary
by MITRE • 09/15/2026
Inspektor Gadget is a set of tools and framework for data collection and system inspection on Kubernetes clusters and Linux hosts using eBPF. From 0.27.0 until 0.53.1, the uprobe library resolver can allow an unprivileged container to consume excessive CPU and block other containers from starting by supplying a crafted /etc/ld.so.cache file while an uprobe-based gadget is active. The parser in pkg/uprobetracer/ldcache_parser.go trusts EntryCount enough to perform excessive iteration, computes cache1Len with overflowing uint32 arithmetic, and repeatedly calls readStringFromBytes in pkg/uprobetracer/bytes.go, where byte-by-byte immutable string concatenation produces quadratic work. While this processing occurs, pkg/container-hook holds the fanotify container-start pause, allowing a crafted cache to delay startup for roughly a minute, prevent Docker from starting other containers, and degrade monitoring. Processing caches from already-running containers can still consume CPU but does not hold the new-container startup pause, and the advisory establishes no confidentiality or integrity impact. This issue is fixed in version 0.53.1.
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Analysis
by VulDB Data Team • 09/15/2026
Inspektor Gadget serves as a comprehensive framework for data collection and system inspection within Kubernetes clusters and Linux hosts, leveraging eBPF technology to provide deep visibility into containerized environments. While designed for legitimate monitoring and debugging purposes, the tooling introduced specific vulnerabilities in versions ranging from 0.27.0 through 0.53.1 that could be exploited by unprivileged containers to disrupt cluster operations. The core of this vulnerability lies within the uprobe library resolver mechanism, which is responsible for parsing dynamic linker cache files such as /etc/ld.so.cache to resolve shared libraries required by eBPF probes. This component failed to adequately validate input data or bound computational complexity, creating a pathway for resource exhaustion attacks that target the availability of container orchestration systems.
The technical flaw originates in the parser implementation located at pkg/uprobetracer/ldcache_parser.go and its interaction with string handling routines in pkg/uprobetracer/bytes.go. When processing an /etc/ld.so.cache file, the parser blindly trusts the EntryCount field without verifying that it corresponds to a reasonable or safe number of entries for iteration. This lack of validation allows an attacker to supply a crafted cache file containing artificially inflated metadata values. Furthermore, during the calculation of cache1Len, the code performs arithmetic operations using uint32 types which are susceptible to integer overflow. When this overflow occurs, it can result in significantly larger or incorrect memory allocation and loop bounds than intended by the developer logic.
Compounding the issue is the method used for string processing within readStringFromBytes. The function employs immutable string concatenation on a byte-by-byte basis rather than using efficient buffer-based approaches like strings.Builder. In Go, this pattern results in quadratic time complexity relative to the length of the input data. When combined with the excessive iteration caused by the untrusted EntryCount and potential integer overflows, the parser enters an infinite or near-infinite loop that consumes nearly all available CPU cycles on the host node. This computational explosion effectively creates a denial-of-service condition for the local system resources required to manage container lifecycles.
The operational impact of this vulnerability is particularly severe due to its interaction with the fanotify-based container start hook mechanism in pkg/container-hook. When Inspektor Gadget monitors containers, it utilizes fanotify to pause the startup process of new containers until inspection data has been collected and processed. During this paused state, if a crafted /etc/ld.so.cache file is present for an incoming container, the parser becomes trapped in its inefficient processing loop. This blocks the release of the start lock for approximately one minute or longer, depending on system load. Consequently, Docker and other container runtimes are prevented from starting not only the malicious container but also any subsequent containers queued behind it. This results in a cascading failure where legitimate workloads cannot be deployed, effectively halting application deployment pipelines and degrading the overall monitoring capabilities of the cluster.
It is important to note that this vulnerability primarily affects availability rather than confidentiality or integrity. The attack does not allow for arbitrary code execution, privilege escalation beyond the unprivileged container context, or data exfiltration from other containers. Additionally, processing cache files associated with already-running containers consumes CPU resources but does not block new container startups because the fanotify pause mechanism is only active during the initial creation phase of a container instance. Therefore, while an attacker could degrade general system performance by forcing repeated parsing of large caches for running workloads, the most critical impact remains the blocking of new service deployments and orchestration delays.
This issue was addressed in version 0.53.1 through rigorous input validation and algorithmic improvements. The fix involves implementing strict bounds checking on EntryCount to ensure it does not exceed expected limits based on file size or system constraints, thereby preventing excessive iteration loops. Additionally, the integer overflow vulnerability in cache length calculation was resolved by using appropriate data types that prevent wrap-around errors during arithmetic operations. To mitigate similar risks in other systems, developers should adhere to CWE-20 for improper input validation and ensure that string processing uses efficient buffering techniques as recommended under CWE-400 regarding uncontrolled resource consumption. Security practitioners monitoring Kubernetes environments running affected versions of Inspektor Gadget are advised to upgrade immediately to version 0.53.1 or later to restore normal container orchestration performance and prevent potential availability disruptions caused by crafted library cache files.