Vulnerability · Published Sep 10, 2026 · Assigned by VulnCheck

CVE-2026-88896EspoCRM before 10.0.4 SSRF via IPv6 Transition Address Bypass

Medium 5.3

In plain English

A medium-severity server-side request forgery in espocrm from espocrm. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 31% of all known vulnerabilities).

Severity (CVSS 3.1)5.3Medium

Exploit odds (30 days)0.4%top 68.8% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

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.

Affected products (as reported)

Vendor	Product	Versions
espocrm	espocrm	0 – before 10.0.4

Weakness: CWE-918 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

References

GitHub Security Advisory (GHSA-xwmh-j8hf-cfqw) vendor-advisory
VulnCheck Advisory: EspoCRM before 10.0.4 SSRF via IPv6 Transition Address Bypass third-party-advisory