Description
fzf 0.36.0 through 0.74.5 contains an inefficient algorithmic complexity vulnerability in maskActionContents that allows local attackers to exhaust the --listen HTTP server through quadratic string concatenation. Attackers can repeatedly send POST bodies of about 1 MB to the unauthenticated localhost port, blocking the single-threaded server for about 30 seconds each time.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| junegunn | fzf | 0.36.0 – ≤ 0.74.5 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | fzf | No fix yet | — |
| Debian 13 | fzf | No fix yet | — |
| Debian 12 | fzf | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | fzf | No fix yet | — |
| Ubuntu 26.04 LTS | fzf | No fix yet | — |
| Ubuntu 24.04 LTS | fzf | No fix yet | — |
| Ubuntu 22.04 LTS | fzf | No fix yet | — |
| Ubuntu 20.04 LTS | fzf | No fix yet | — |
References
- Patch Commit patch
- https://github.com/junegunn/fzf/blob/v0.74.5/src/options.go#L1680-L1736 technical-description
- https://github.com/junegunn/fzf product
- VulnCheck Advisory: fzf 0.36.0 through 0.74.5 Denial of Service via maskActionContents third-party-advisory