ffuf denial of service (OOM) via HTTP response decompression bomb
cve-program · CVE-2026-73232
Publishedffuf is a fast web fuzzer written in Go. Prior to 2.2.0, ffuf allows a malicious target server to cause an out-of-memory denial of service because the response size guard in pkg/runner/simple.go checks only the compressed Content-Length while io.ReadAll reads gzip, brotli, deflate, transparently decompressed, or chunked response bodies without a decompressed-size bound. This issue is fixed in version 2.2.0.
Read the publisher's advisoryeuvd · EUVD-2026-56926
Publishedffuf is a fast web fuzzer written in Go. Prior to 2.2.0, ffuf allows a malicious target server to cause an out-of-memory denial of service because the response size guard in pkg/runner/simple.go checks only the compressed Content-Length while io.ReadAll reads gzip, brotli, deflate, transparently decompressed, or chunked response bodies without a decompressed-size bound. This issue is fixed in version 2.2.0.
Read the publisher's advisorynvd · CVE-2026-73232
Publishedffuf is a fast web fuzzer written in Go. Prior to 2.2.0, ffuf allows a malicious target server to cause an out-of-memory denial of service because the response size guard in pkg/runner/simple.go checks only the compressed Content-Length while io.ReadAll reads gzip, brotli, deflate, transparently decompressed, or chunked response bodies without a decompressed-size bound. This issue is fixed in version 2.2.0.
Read the publisher's advisoryosv · GHSA-jcvh-xf52-2cwm
Published### 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: 1. **gzip (default configuration):** the transport requests gzip on its own and transparently decompresses the response, stripping `Content-Encoding` and `Content-Length`, so the size check is skipped and the already-decoded body is read unbounded. 2. **brotli/deflate (or gzip with headers preserved):** `Content-Length` reflects the small compressed size and passes the check; the body is then manually decompressed into an unbounded `io.ReadAll`. 3. **chunked transfer encoding:** no `Content-Length` header 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).
Read the publisher's advisoryosv · GO-2026-6369
Publishedffuf denial of service (OOM) via HTTP response decompression bomb in github.com/ffuf/ffuf
Read the publisher's advisoryAffected versions, risk and source history
Exploitation and risk
Source statusCISA KEV lists vulnerabilities known to be exploited. FIRST EPSS estimates the likelihood of exploitation in the next 30 days. An unavailable score does not mean zero risk.
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cve-program · CVE-2026-73232
Publishedffuf denial of service (OOM) via HTTP response decompression bomb
ffuf is a fast web fuzzer written in Go. Prior to 2.2.0, ffuf allows a malicious target server to cause an out-of-memory denial of service because the response size guard in pkg/runner/simple.go checks only the compressed Content-Length while io.ReadAll reads gzip, brotli, deflate, transparently decompressed, or chunked response bodies without a decompressed-size bound. This issue is fixed in version 2.2.0.
- Source published
- 11 Aug 2026 19:32:48 UTC
- Source modified
- 12 Aug 2026 12:59:07 UTC
- Saved here
- 23 Oct 2026 15:48:27 UTC
- Source terms
- CVE Program Terms of Use
Original source record · Cite this exact observation · Complete original publisher JSON
Source: cve-program · CVE Program Terms of Use. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.
CVSS 3.1 · 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
euvd · EUVD-2026-56926
Publishedffuf is a fast web fuzzer written in Go. Prior to 2.2.0, ffuf allows a malicious target server to cause an out-of-memory denial of service because the response size guard in pkg/runner/simple.go checks only the compressed Content-Length whi…
ffuf is a fast web fuzzer written in Go. Prior to 2.2.0, ffuf allows a malicious target server to cause an out-of-memory denial of service because the response size guard in pkg/runner/simple.go checks only the compressed Content-Length while io.ReadAll reads gzip, brotli, deflate, transparently decompressed, or chunked response bodies without a decompressed-size bound. This issue is fixed in version 2.2.0.
Additional publisher context
EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON.
Original publisher date fields
datePublished: Aug 11, 2026, 7:32:48 PM
dateUpdated: Aug 12, 2026, 12:59:07 PM
- Source published
- Aug 11, 2026, 7:32:48 PM (timezone not stated)
- Source modified
- Aug 12, 2026, 12:59:07 PM (timezone not stated)
- Saved here
- 11 Nov 2026 17:11:11 UTC
- Source terms
- ENISA EUVD · source terms and attribution apply
Original source record · Cite this exact observation · Complete original publisher JSON
Source: euvd · ENISA EUVD · source terms and attribution apply. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.
EUVD CVSS 3.1 · 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
nvd · CVE-2026-73232
Publishedffuf is a fast web fuzzer written in Go. Prior to 2.2.0, ffuf allows a malicious target server to cause an out-of-memory denial of service because the response size guard in pkg/runner/simple.go checks only the compressed Content-Length whi…
ffuf is a fast web fuzzer written in Go. Prior to 2.2.0, ffuf allows a malicious target server to cause an out-of-memory denial of service because the response size guard in pkg/runner/simple.go checks only the compressed Content-Length while io.ReadAll reads gzip, brotli, deflate, transparently decompressed, or chunked response bodies without a decompressed-size bound. This issue is fixed in version 2.2.0.
Additional publisher context
NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON.
Source analysis status: Deferred
Weakness classifications: CWE-409
Original publisher date fields
published: 2026-08-11T20:18:48.543
lastModified: 2026-09-18T20:09:01.757
- Source published
- 11 Aug 2026 20:18:48 UTC
- Source modified
- 18 Sep 2026 20:09:01 UTC
- Saved here
- 25 Oct 2026 15:19:03 UTC
- Source terms
- NIST NVD usage terms; underlying source attribution retained
Original source record · Cite this exact observation · Complete original publisher JSON
Source: nvd · NIST NVD usage terms; underlying source attribution retained. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.
CVSS 3.1 · [email protected] · Secondary · 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
osv · GHSA-jcvh-xf52-2cwm
Publishedffuf denial of service (OOM) via HTTP response decompression bomb
### 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: 1. **gzip (default configuration):** the transport requests gzip on its own and transparently decompresses the response, stripping `Content-Encoding` and `Content-Length`, so the size check is skipped and the already-decoded body is read unbounded. 2. **brotli/deflate (or gzip with headers preserved):** `Content-Length` reflects the small compressed size and passes the check; the body is then manually decompressed into an unbounded `io.ReadAll`. 3. **chunked transfer encoding:** no `Content-Length` header 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).
- Source published
- 3 Sep 2026 18:02:09 UTC
- Source modified
- 10 Sep 2026 15:25:52 UTC
- Saved here
- 24 Oct 2026 13:19:41 UTC
- Source terms
- GitHub Advisory Database · CC-BY-4.0
Original source record · Cite this exact observation · Complete original publisher JSON
Source: osv · GitHub Advisory Database · CC-BY-4.0. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.
CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Publisher rating · HIGH
osv · GO-2026-6369
Publishedffuf denial of service (OOM) via HTTP response decompression bomb in github.com/ffuf/ffuf
ffuf denial of service (OOM) via HTTP response decompression bomb in github.com/ffuf/ffuf
- Source published
- 10 Sep 2026 14:48:42 UTC
- Source modified
- 10 Sep 2026 15:15:13 UTC
- Saved here
- 24 Oct 2026 13:19:41 UTC
- Source terms
- OSV · upstream source license applies
Original source record · Cite this exact observation · Complete original publisher JSON
Source: osv · OSV · upstream source license applies. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.