CVE-2026-53433
CVE-2026-53433 is a high-severity vulnerability in Junegunn Fzf with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-407.
Key facts
- Severity: High (CVSS 3.x base score 7.5)
- CVSS v4: 5.7
- EPSS exploit prediction: 0% (12th percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-407
- Affected product: Junegunn Fzf
- Published:
- Last modified:
Description
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.
Frequently asked questions
- What is CVE-2026-53433?
- 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.
- How severe is CVE-2026-53433?
- CVE-2026-53433 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
- Is CVE-2026-53433 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (12th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2026-53433?
- CVE-2026-53433 affects Junegunn Fzf. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2026-53433?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- When was CVE-2026-53433 published?
- CVE-2026-53433 was published on 2026-06-30 and last updated on 2026-07-02.
References
- https://cert.pl/en/posts/2026/06/CVE-2026-53432
- https://github.com/junegunn/fzf
- https://github.com/junegunn/fzf/commit/7963a2c6586c0b9eaa89b8995de8f0e08cf8a4ce
Affected products (1)
- cpe:2.3:a:junegunn:fzf:*:*:*:*:*:*:*:*
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