Description

Previously, resolving relative paths containing parent directory ('..') segments performed string conversions and buffer rewrites on each step, resulting in quadratic time complexity and high memory allocation overhead. Now, path resolution operates on a byte buffer using index-based backtracking for '..' segments, eliminating the quadratic time complexity and significantly reducing memory allocations.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "5.9",
  "pubDate": "2026-08-13T22:17:22.440Z",
  "pubdate": "2026-08-13T22:17:22.440Z",
  "executiveSummary": "This advisory details an algorithmic complexity vulnerability concerning path resolution mechanisms involving parent directory traversal segments. Historically, the processing of relative paths containing multiple parent directory segments ('..') relied upon iterative string conversions and individual buffer rewrites executed at each step of the resolution lifecycle. This implementation design introduced a quadratic time complexity performance profile, accompanied by substantial memory allocation overhead during path normalization routines. The primary risk implication associated with this flaw is resource exhaustion, specifically denial of service conditions driven by algorithmic degradation when handling maliciously crafted path inputs. The vulnerability impacts software components responsible for parsing and normalizing file system paths or URI routes. An unauthenticated attacker capable of supplying specially crafted input strings featuring numerous parent directory segments can deliberately trigger excessive CPU consumption and memory allocation spikes, exhausting system resources and destabilizing the host application. Exploitation requires no advanced privileges or complex network positioning, relying solely on the ability to submit targeted path strings to the vulnerable parsing interface.",
  "technicalDetails": "The root cause of the vulnerability resides in inefficient string manipulation algorithms utilized during the normalization and resolution of relative paths containing parent directory ('..') sequences. In the vulnerable implementation, the parsing engine performed iterative string conversions and buffer rewrites sequentially for every individual segment encountered within the input path. As the number of parent directory segments scaled, the computational workload increased quadratically (O(n^2)), severely degrading parsing throughput and inflating memory allocation demands. The vulnerable component is the path resolution and normalization module responsible for translating input paths into canonical forms. During a typical attack flow, an adversary submits an input string containing an extensive sequence of '..' tokens designed to maximize the iteration count of the path parser. Upon receiving this input, the vulnerable component initiates the flawed string transformation and buffer rewriting loop. Because the algorithm recalculates and modifies the buffer state at each traversal step, the CPU expenditure escalates rapidly, monopolizing processing threads and inducing high memory thrashing. No authentication or elevated privileges are required to initiate this behavior, provided the vulnerable parsing endpoint is reachable via the network or exposed through local application interfaces. The post-exploitation impact is primarily concentrated on availability, manifesting as application unresponsiveness, thread starvation, or outright crashes due to memory exhaustion or timeouts triggered by prolonged execution times in the parsing routine."
}