Summary
ffuf denial of service (OOM) via HTTP response decompression bomb
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 unbounded
io.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).
Impact
CVE-2026-73232 has a CVSS score of 7.5 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (2.2.0); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2026-73232? CVE-2026-73232 is a high-severity security vulnerability in github.com/ffuf/ffuf/v2 (go), affecting versions <= 2.1.0. It is fixed in 2.2.0.
- How severe is CVE-2026-73232? CVE-2026-73232 has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which packages are affected by CVE-2026-73232?
github.com/ffuf/ffuf/v2(go) (versions <= 2.1.0)github.com/ffuf/ffuf(go) (versions <= 1.5.0)
- Is there a fix for CVE-2026-73232? Yes. CVE-2026-73232 is fixed in 2.2.0. Upgrade to this version or later.
- Is CVE-2026-73232 exploitable, and should I be worried? Whether CVE-2026-73232 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-73232 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-73232? Upgrade
github.com/ffuf/ffuf/v2to 2.2.0 or later.