CVE-2026-73232 is a high-severity (CVSS 7.5) CWE-409 vulnerability in github.com/ffuf/ffuf/v2. A fix is available for github.com/ffuf/ffuf/v2 — see the affected versions and patch details below.
ffuf denial of service (OOM) via HTTP response decompression bomb
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-73232.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2026-73232 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 383,485 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
github.com/ffuf/ffuf/v2🐹github.com/ffuf/ffufReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Summary
A malicious or attacker-controlled target server can crash ffuf with an out-of-memory condition by returning a compressed HTTP response that decompresses to a very large body (a decompression bomb). This works against default usage with no special flags.
Details
The response body size guard in pkg/runner/simple.go only checks the server-supplied Content-Length header, which reflects the compressed size and is absent for chunked responses or when Go's
net/http transport transparently decompresses the body. After that check, io.ReadAll reads the entire decompressed stream into memory with no upper bound, so a small compressed body that
expands to gigabytes causes unbounded allocation and the process is terminated by the OS OOM killer.
The guard is bypassed in three independent ways:
- gzip (default configuration): the transport requests gzip on its own and transparently decompresses the response, stripping
Content-EncodingandContent-Length, so the size check is skipped and the already-decoded body is read unbounded. - brotli/deflate (or gzip with headers preserved):
Content-Lengthreflects the small compressed size and passes the check; the body is then manually decompressed into an unboundedio.ReadAll. - chunked transfer encoding: no
Content-Lengthheader is present, so the numeric parse fails and the check is skipped entirely.
Impact
Denial of service against the operator running ffuf. A single hostile endpoint can OOM-kill ffuf on a default invocation such as ffuf -u http://target/FUZZ -w wordlist.txt, discarding all
in-memory scan results. Because the crash recurs on every attempt against that target, a server can effectively make itself immune to ffuf-based content discovery. There is no confidentiality or
integrity impact; only the availability of the scanning process is affected. CVSS 3.1 base score 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H), CWE-409 (Improper Handling of Highly Compressed Data).
Patches
Fixed in ffuf 2.2.0 (https://github.com/ffuf/ffuf/releases/tag/v2.2.0) via https://github.com/ffuf/ffuf/pull/897. The response body read is now bounded with io.LimitReader to the existing 5
MB download cap regardless of Content-Encoding, chunked framing, or transport-level decompression; responses exceeding the cap are dropped rather than read into memory. Upgrade to 2.2.0 or later.
Workarounds
There is no configuration flag that fully mitigates this in affected versions. Until upgrading, limit ffuf usage against untrusted or attacker-influenced targets. Upgrading to 2.2.0 is the fix.
Credits
Reported by João Tricta (Hakai Offensive Security).
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/ffuf/ffuf/v2 | all versions | 2.2.0go get github.com/ffuf/ffuf/v2@v2.2.0 |
| 🐹Go | github.com/ffuf/ffuf | all versions | No fix |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/ffuf/ffuf/v2, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/ffuf/ffuf/v2 to 2.2.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-73232 is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.
Frequently Asked Questions
Is CVE-2026-73232 in your dependencies?
Find it across Go, including transitive dependencies.