SSRF in Http4s
CVE-2021-41084
http4s is an open source scala interface for HTTP. In affected versions http4s is vulnerable to response-splitting or request-splitting attacks when untrusted user input is used to create any of the following fields: Header names (`Header.name`å), Header values (`Header.value`), Status reason phrases (`Status.reason`), URI paths (`Uri.Path`), URI authority registered names (`URI.RegName`) (through 0.21). This issue has been resolved in versions 0.21.30, 0.22.5, 0.23.4, and 1.0.0-M27 perform the following. As a matter of practice http4s services and client applications should sanitize any user input in the aforementioned fields before returning a request or response to the backend. The carriage return, newline, and null characters are the most threatening.
Vulnerability class: SSRF (Server-Side Request Forgery)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.7 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N.
EPSS exploit prediction
EPSS: 0.012 (67.8th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 68th percentile — 67.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.012 · newest: 0.012 · change: 0.000
Affected products
- Http4s — versions <= 0.21.28, >= 0.22.0, < 0.22.5, >= 0.23.0, < 0.23.4
- Typelevel Http4s — versions 1.0.0
Weakness classification (CWE)
References
- github.com/http4s/http4s/security/advisories/GHSA-5vcm-3xc3-w7x3 (Exploit, Third Party Advisory)
- github.com/http4s/http4s/commit/d02007db1da4f8f3df2dbf11f1db9ac7afc3f9d8 (Patch, Third Party Advisory)
- httpwg.org/http-core/draft-ietf-httpbis-semantics-latest.html (Vendor Advisory)
- owasp.org/www-community/attacks/HTTP_Response_Splitting (Third Party Advisory)
Frequently asked questions
- What is CVE-2021-41084?
- CVE-2021-41084 is a high-severity vulnerability in Http4s, classified under Server-Side Request Forgery (SSRF). CVSS score: 8.7/10. Published 2021-09-21.
- How severe is CVE-2021-41084?
- High severity. CVSS v3 base score is 8.7 out of 10.