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CVE-2026-88896

EspoCRM before 10.0.4 SSRF via IPv6 Transition Address Bypass

CVSS 4.0 6.9 MEDIUMCVSS 3.1 5.3 MEDIUMCheck source for fixed versionsKEV status unknown

Original advisory

cve-program · CVE-2026-88896

Published

EspoCRM before 10.0.4 is vulnerable to server-side request forgery. HostCheck::ipAddressIsNotInternal(), which validates outbound URLs to block requests to internal/private IP addresses, strips ::ffff: (IPv4-mapped IPv6) prefixes but does not recognize IPv6 transition addresses that embed private IPv4 addresses: NAT64 (64:ff9b::), 6to4 (2002::), and Teredo (2001:0000::). An attacker who controls a domain with AAAA records pointing to such transition addresses can bypass both the internal-host validation and the CURLOPT_RESOLVE IP-pinning check, causing EspoCRM to issue outbound requests to internal network services. Affected paths include POST /Attachment/fromImageUrl, reachable by any authenticated user with attachment access, and outbound webhook delivery, which requires an admin or API user.

Read the publisher's advisory

Affected versions, risk and source history

cve-program · CVE-2026-88896

Published

espocrm

Vendor product

Publisher's version information

Shown as published. These rules are not interpreted as NuGet package version ranges.

{
                    "vendor": "espocrm",
                    "product": "espocrm",
                    "defaultStatus": "unaffected",
                    "versions": [
                        {
                            "version": "0",
                            "status": "affected",
                            "versionType": "semver",
                            "lessThan": "10.0.4"
                        },
                        {
                            "version": "10.0.4",
                            "status": "unaffected",
                            "versionType": "semver"
                        }
                    ]
                }

Original source record · Cite this exact observation · Complete original publisher JSON