CVE-2026-88896 EspoCRM before 10.0.4 SSRF via IPv6 Transition Address Bypass
Authenticated attackers can bypass IP validation using IPv6 transition addresses to force EspoCRM to make requests to internal network services.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-88896?
CVE-2026-88896 is a medium-severity server-side request forgery vulnerability in espocrm, published on 10 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
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.
Weakness: CWE-918
Which versions are affected by CVE-2026-88896?
How do I fix CVE-2026-88896?
No fix has been published for CVE-2026-88896 yet. Limit exposure of the affected software until one is available.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is CVE-2026-88896 being exploited?
There is no known exploitation of CVE-2026-88896 in the wild and no public exploit code.
Sources
Also known as GHSA-p98c-469w-949w, GHSA-xwmh-j8hf-cfqw.