CVE-2026-53433
HighCVSS 7.5Exploitation Probability (EPSS)
Low risk12th percentile - higher than 12% of all known CVEs
Summary
A vulnerability in fzf's --listen mode causes a Denial of Service (DoS) due to inefficient HTTP body processing using repeated string concatenation, resulting in quadratic time complexity (O(n²)). A crafted POST request with many small segments can trigger excessive CPU usage, monopolizing the single-threaded HTTP server and blocking all other clients.
Risk Assessment
The risk is that a single malicious request can completely block the HTTP server in --listen mode, causing service unavailability for all other users.
Recommendation
Immediately update fzf to version 0.73.1 or later, which contains the fix for this vulnerability.
Other vulnerabilities in fzf
See all- CVE-2026-115319Low
fzf versions 0.36.0 through 0.74.5 contain an inefficient algorithmic complexity vulnerability in maskActionContents that lets local attackers exhaust the --listen HTTP server via quadratic string concatenation. Repeatedly sending ~1 MB POST bodies to the unauthenticated localhost port blocks the single-threaded server for about 30 seconds each time.
- CVE-2026-53432High
An integer overflow vulnerability was discovered in the fzf tool within the FuzzyMatchV2 function. When the input line length is approximately 2,200,000 bytes and the pattern length is 999 bytes, an overflow occurs, leading to invalid slice bounds. The Go runtime detects this and immediately terminates the process with a non-recoverable panic.
Original NVD description (English source)
fzf is vulnerable to a Denial of Service (DoS) due to inefficient HTTP body processing in the --listen mode due to inefficient HTTP body processing using repeated string concatenation, resulting in quadratic time complexity (O(n²)). A crafted POST request with many small segments can trigger excessive CPU usage during request handling.This allows a single malicious request to monopolize the single‑threaded HTTP server, blocking all other clients and resulting in denial of service. This issue was fixed in version 0.73.1.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS