CVE-2026-53433
Denial of Service in fzf
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.
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
Denial of Service in fzf
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.
- Record
CVE-2026-53433- CVSS 4.0
- 5.7 Medium
CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N - Weakness
- CWE-407
- Updated
- 2026-11-02
EUVDEUVD-2026-40303
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.
- Record
EUVD-2026-40303- CVSS 4.0
- 5.7 Medium
CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-mvmf-94v6-879g
fzf vulnerable to denial of service through quadratic HTTP request-body accumulation
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.
- Record
GHSA-mvmf-94v6-879g- CVSS 4.0
- 5.7 Medium
CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N - Weakness
- CWE-407
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2026-53433- CVSS 4.0
- 5.7 Medium
CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-407
- Updated
- 2026-11-02
OSV
Denial of Service in fzf
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.
- Record
CVE-2026-53433- CVSS 4.0
- 5.7 Medium
CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N - Weakness
- CWE-407
- Updated
- 2026-11-02
OSVDEBIAN-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.
- Record
DEBIAN-CVE-2026-53433- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVGHSA-mvmf-94v6-879g
fzf vulnerable to denial of service through quadratic HTTP request-body accumulation
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.
- Record
GHSA-mvmf-94v6-879g- CVSS 4.0
- 5.7 Medium
CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N - Weakness
- CWE-407
- Updated
- 2026-11-02
OSVUBUNTU-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.
- Record
UBUNTU-CVE-2026-53433- CVSS 4.0
- 5.7 Medium
CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N - CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVGO-2026-6620 No score
fzf vulnerable to denial of service through quadratic HTTP request-body accumulation in github.com/junegunn/fzf
fzf vulnerable to denial of service through quadratic HTTP request-body accumulation in github.com/junegunn/fzf
- Record
GO-2026-6620- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
github.com/junegunn/fzfGo |
before 0.73.1 | 0.73.1 |
fzfDebian:12 |
All versions, plus listed versions 0.38.0-10.42.0-10.44.1-10.46.1-10.55.0-1 Show 17 moreShow less0.56.3-10.57.0-10.58.0-10.60.0-10.60.1-10.60.2-10.60.3-10.64.0-10.65.1-10.66.0-10.67.0-10.70.0-10.72.0-10.73.1-10.74.1-10.74.3-10.74.4-1 |
None known |
fzfDebian:13 |
All versions, plus listed versions 0.60.3-10.64.0-10.65.1-10.66.0-10.67.0-1 Show 6 moreShow less0.70.0-10.72.0-10.73.1-10.74.1-10.74.3-10.74.4-1 |
None known |
fzfDebian:14 |
before 0.73.1-1, plus listed versions 0.60.3-10.64.0-10.65.1-10.66.0-10.67.0-10.70.0-10.72.0-1 |
0.73.1-1 |
fzfUbuntu:20.04:LTS |
All versions, plus listed versions 0.18.0-20.18.0-30.19.0-10.20.0-10.20.0-1ubuntu0.1 |
None known |
fzfUbuntu:22.04:LTS |
All versions, plus listed versions 0.24.3-10.29.0-10.29.0-1ubuntu0.1 |
None known |
fzfUbuntu:24.04:LTS |
All versions, plus listed versions 0.42.0-1build10.44.1-10.44.1-1ubuntu0.10.44.1-1ubuntu0.20.44.1-1ubuntu0.3 |
None known |
fzfUbuntu:25.10 |
All versions, plus listed versions 0.60.3-1 |
None known |
fzfUbuntu:26.04:LTS |
All versions, plus listed versions 0.60.3-10.66.0-10.67.0-1 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-53433 is a medium vulnerability (CVSS 5.7) in Fzf, published June 30, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.38%, the 31st percentile. Fixed in github.com/junegunn/fzf 0.73.1.