CVE-2021-40438
Apache HTTP Server-Side Request Forgery (SSRF)
CVSS
9.0
Critical
EPSS
100.0%
p100
KEV
YES
Dec 1, 2021
Exploit Today
80
0-100
Published: Sep 16, 2021 · Last modified: Aug 6, 2026 · CWE-918
100.0%EPSS · 30 days100.0%
2026-09-162026-10-14
Product
Apache / Apache
Vulnerability
Apache HTTP Server-Side Request Forgery (SSRF)
Added to KEV
Dec 1, 2021
Remediate by
Dec 15, 2021
Known ransomware use
Yes
Summary description
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.
Required action
Apply updates per vendor instructions.
Notes
https://nvd.nist.gov/vuln/detail/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.
- cert-portal.siemens.comhttps://cert-portal.siemens.com/productcert/pdf/ssa-685781.pdf
- httpd.apache.orghttps://httpd.apache.org/security/vulnerabilities_24.html
- lists.apache.orghttps://lists.apache.org/thread.html/r210807d0bb55f4aa6fbe1512be6bcc4dacd64e84940429fba329967a%40%3Cusers.httpd.apache.org%3E
- lists.apache.orghttps://lists.apache.org/thread.html/r2eb200ac1340f69aa22af61ab34780c531d110437910cb9c0ece3b37%40%3Cbugs.httpd.apache.org%3E
- lists.apache.orghttps://lists.apache.org/thread.html/r3925e167d5eb1c75def3750c155d753064e1d34a143028bb32910432%40%3Cusers.httpd.apache.org%3E
- lists.apache.orghttps://lists.apache.org/thread.html/r61fdbfc26ab170f4e6492ef3bd5197c20b862ce156e9d5a54d4b899c%40%3Cusers.httpd.apache.org%3E
- lists.apache.orghttps://lists.apache.org/thread.html/r82838efc5fa6fc4c73986399c9b71573589f78b31846aff5bd9b1697%40%3Cusers.httpd.apache.org%3E
- lists.apache.orghttps://lists.apache.org/thread.html/r82c077663f9759c7df5a6656f925b3ee4f55fcd33c889ba7cd687029%40%3Cusers.httpd.apache.org%3E
- lists.apache.orghttps://lists.apache.org/thread.html/rf6954e60b1c8e480678ce3d02f61b8a788997785652e9557a3265c00%40%3Cusers.httpd.apache.org%3E
- lists.debian.orghttps://lists.debian.org/debian-lts-announce/2021/10/msg00001.html
- lists.fedoraproject.orghttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SPBR6WUYBJNACHKE65SPL7TJOHX7RHWD/
- lists.fedoraproject.orghttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZNCYSR3BXT36FFF4XTCPL3HDQK4VP45R/
- security.gentoo.orghttps://security.gentoo.org/glsa/202208-20
- security.netapp.comhttps://security.netapp.com/advisory/ntap-20211008-0004/
- tools.cisco.comhttps://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-httpd-2.4.49-VWL69sWQ
- www.debian.orghttps://www.debian.org/security/2021/dsa-4982
- www.oracle.comhttps://www.oracle.com/security-alerts/cpuapr2022.html
- www.oracle.comhttps://www.oracle.com/security-alerts/cpujan2022.html
- www.tenable.comhttps://www.tenable.com/security/tns-2021-17
- cert-portal.siemens.comhttps://cert-portal.siemens.com/productcert/pdf/ssa-685781.pdf
CVECVSSEPSSKEVRExploitTitleMod.
CVE-2026-1108688.5 HIG—
——0Renovate before 44.79.0 contains a server-side request forgery vulnerability that allows users to make the shared HTTP client request arbitrary internal URLs via extends presets or customDatasources. Attackers can point a preset at an instance metadata service endpoint to obtain AWS credentials or leak sensitive information through Renovate logs.8hCVE-2026-0311——
——0A server-side request forgery vulnerability in Palo Alto Networks Checkov by Prisma® Cloud enables a local unauthenticated user to make unauthorized network requests from host to internal services.10hCVE-2026-553856.8 MED—
——0InvoiceShelf is an open-source web & mobile app that helps track expenses, payments and create professional invoices and estimates. Prior to version 2.4.0, InvoiceShelf's PDFConfigurationRequest.php validates the owner-controlled gotenberg_host setting only as a syntactically valid URL. GotenbergPDFDriver::loadView later sends a multipart HTTP request containing rendered invoice, estimate, or payment HTML as document.html to that host without rejecting private, loopback, link-local, or reserved addresses. An owner can use PDF generation to reach internal services or cloud metadata endpoints, and a configured external host receives customer names, addresses, line items, totals, and company identifiers from subsequent PDF renders. This issue is fixed in version 2.4.0.11hCVE-2026-557877.1 HIG—
——0Flyto2 Core is an execution kernel for automation and AI-agent workflows. Prior to 2.26.3, validate_url_ssrf and is_private_ip in src/core/utils.py compare resolved addresses only against native private IPv4 and IPv6 ranges and do not unwrap IPv4-mapped, IPv4-compatible, 6to4, or NAT64 transition addresses. An authenticated workflow author can provide a transition-form literal URL through the Execution API POST /v1/execute route, http.get, or sibling guarded outbound-request modules, causing the guard to accept an address whose embedded IPv4 points to loopback, RFC 1918, or cloud metadata services. On a host that routes the selected transition form, the outbound request reaches the internal destination and returns the response body to the workflow caller, enabling read SSRF and disclosure of internal-service data or cloud credentials. This issue is fixed in version 2.26.3.12hCVE-2026-1023546.8 MED—
——0BentoPDF is a privacy-focused PDF toolkit that runs in the browser. In versions through 2.8.6, cloudflare/cors-proxy-worker.js performs a DNS-over-HTTPS safety check in hostnameResolvesToPrivate(), as used by isValidCertificateUrl() and isValidTsaUrl(), separately from the outbound fetch(targetUrl, ...). In deployments where PROXY_SECRET validation is not enabled, a direct client that controls authoritative DNS can forge the Origin header, supply a certificate, OCSP, CRL, or TSA URL that passes the proxy's accepted path checks, return a public address during validation, and return a private or link-local address during the later fetch. The endpoint can return allowed response bodies to the attacker, but exploitation requires precise timing, redirects and IP-literal obfuscation are blocked, and network reachability limits the target. This vulnerability is fixed in 2.8.7.12hCVE-2026-76083——
——0Redash is a package for data visualization and sharing. From 10.0.0 until 26.9.0, the JSON data source query runner in redash/query_runner/json_ds.py used _get_all_results() to combine its configured base_url with a user-supplied query URL by using urljoin. An absolute query URL replaced the configured base URL instead of remaining under it, allowing a user with execute_query permission to direct a server-side request to an arbitrary external origin. When HTTP Basic Auth was configured for the data source, the request also forwarded those credentials to the selected origin. Private and internal address access remained constrained when REDASH_ENFORCE_PRIVATE_IP_BLOCK was enabled. This issue is fixed in version 26.9.0.13h