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
Affects fzfSource GCVE Database
Not known to be exploited · CVSS 2.0 Low.
Data as of 28 Oct 2026, 22:31 UTC
CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 22 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10fzfpkg:deb/ubuntu/fzf?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSfzfpkg:deb/ubuntu/fzf?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSfzfpkg:deb/ubuntu/fzf?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 22.04 LTSfzfpkg:deb/ubuntu/fzf?arch=source&distro=jammyOther threats | Affected
| Fixed in– |
Ubuntu 20.04 LTSfzfpkg:deb/ubuntu/fzf?arch=source&distro=focalOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
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.
References
- ubuntu.com/security/CVE-2026-115319 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-115319 (opens in a new tab)
- github.com/junegunn/fzf (opens in a new tab)
- github.com/junegunn/fzf/blob/v0.74.5/src/options.go (opens in a new tab)
- github.com/junegunn/fzf/commit/b412a450538e5f4a1d7057732e75d945dafa18a6 (opens in a new tab)
- vulncheck.com/advisories/fzf-0.36.0-through-0.74.5-denial-of-service-via-maskactioncontents (opens in a new tab)