High [CVE-2026-53433] Denial of Service via inefficient HTTP body processing
This high-severity Red Hat Linux advisory covers CVE-2026-53433.
Aggregated and source-linked by VulniPulse. Data sources, validation and limitations.
VulniPulse record published Record updated
Summary
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.
A flaw was found in fzf, a command-line fuzzy finder. This vulnerability allows a remote attacker to cause a Denial of Service (DoS) by sending a crafted POST request with many small segments to the `--listen` mode.
The inefficient HTTP body processing, which uses repeated string concatenation, leads to quadratic time complexity, causing excessive CPU usage and blocking other clients.
Red Hat has corrected the impact from IMPORTANT to MODERATE — the original AI-Bot CVSS of 7.5 (AV:N/AC:L) did not account for the --listen mode being a non-default feature that must be explicitly enabled. The CVEORG CVSSv4 score of 5.7 (AV:L/AT:P) more accurately reflects the prerequisite nature of the attack.
Weakness: CWE-1046.
Is CVE-2026-53433 exploited?
No exploitation is reported in the sources VulniPulse tracks: CVE-2026-53433 is not in the CISA KEV catalog (checked ) and this advisory does not report exploitation. That is not proof the vulnerability cannot be exploited.
How do I fix CVE-2026-53433?
Upgrade to a fixed release named by Red Hat:
- 0.73.1
Confirm against the vendor advisory before you patch.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative. Check it before change work.
Official advisory · high-confidence parse· fetched 12 days ago·verify at source
Mitigation checklist
- Do not use fzf's --listen mode in untrusted network environments. If --listen is required, restrict network access to the fzf listener port using firewall rules.
Official advisory · high-confidence parse· fetched 12 days ago·verify at source
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