SSRF in Apache Software Foundation Http Server
CVE-2021-40438
A crafted request uri-path can cause mod_proxy to forward the request to an origin server choosen by the remote user. This issue affects Apache HTTP Server 2.4.48 and earlier.
Vulnerability class: SSRF (Server-Side Request Forgery)
EPSS: 0.944 (100.0th percentile) — read the EPSS interpretation.
Affected products
- Apache Software Foundation Http Server — versions Apache HTTP Server 2.4
Weakness classification (CWE)
CISA KEV (Known Exploited Vulnerabilities)
This CVE is on the CISA KEV catalog, added on . CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.
BOD 22-01 due date: .
Required action: Apply updates per vendor instructions.
Public proof-of-concept exploits
- sixpacksecurity/CVE-2021-40438
- sergiovks/CVE-2021-40438-Apache-2.4.48-SSRF-exploit
- xiaojiangxl/CVE-2021-40438
- BabyTeam1024/CVE-2021-40438
- Cappricio-Securities/CVE-2021-40438
- gassara-kys/CVE-2021-40438
- pisut4152/Sigma-Rule-for-CVE-2021-40438-exploitation-attempt
- n0m-d/CVE-2021-40438-POC
- yakir2b/check-point-gateways-rce
- ericmann/apache-cve-poc
References
- httpd.apache.org/security/vulnerabilities_24.html (x_refsource_MISC)
- FEDORA-2021-dce7e7738e (vendor-advisory, x_refsource_FEDORA)
- [httpd-users] 20210923 [users@httpd] 2.4.49 security fixes: more info (mailing-list, x_refsource_MLIST)
- [httpd-users] 20210923 Re: [users@httpd] 2.4.49 security fixes: more info (mailing-list, x_refsource_MLIST)
- [httpd-users] 20210923 [users@httpd] Re: [External] : [users@httpd] 2.4.49 security fixes: more info (mailing-list, x_refsource_MLIST)
- [httpd-users] 20210923 Re: [users@httpd] Re: [External] : [users@httpd] 2.4.49 security fixes: more info (mailing-list, x_refsource_MLIST)
- FEDORA-2021-e3f6dd670d (vendor-advisory, x_refsource_FEDORA)
- [debian-lts-announce] 20211002 [SECURITY] [DLA 2776-1] apache2 security update (mailing-list, x_refsource_MLIST)
- [httpd-bugs] 20211008 [Bug 65616] CVE-2021-36160 regression (mailing-list, x_refsource_MLIST)
- DSA-4982 (vendor-advisory, x_refsource_DEBIAN)
Frequently asked questions
- What is CVE-2021-40438?
- CVE-2021-40438 is a vulnerability in Apache Software Foundation Http Server, classified under Server-Side Request Forgery (SSRF). Published 2021-09-16.
- Is CVE-2021-40438 known to be exploited?
- Yes. CVE-2021-40438 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2021-12-01), indicating it is being actively exploited. 73 public proof-of-concept repositories are indexed.