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Vulnerabilities

Vulnerability · CVE-2026-88896

SSRF via IPv6 transition address bypass of internal-host validation

Published Aug 13, 2026 · catalog updated Sep 14, 2026 · SSRF via IPv6 transition

Last checked Nov 2, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-88896. EPSS is 0.37%. Act only if a listed version of SSRF via IPv6 transition is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (SSRF via IPv6 transition).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Low—
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.37%
Remediation
Version ranges on file
Affected products
composer espocrm/espocrm

## Summary EspoCRM's validates outbound URLs to block requests to internal/private IP addresses. The check strips (IPv4-mapped IPv6) prefixes but does not recognize IPv6 transition addresses that embed private IPv4 addresses: NAT64 ( ), 6to4 ( ), and Teredo ( ). An attacker controlling a domain with AAAA DNS records pointing to these transition addresses can bypass both the host validation check and the CURLOPT_RESOLVE IP-pinning check, causing EspoCRM to issue outbound requests to internal network services. Affected endpoints include (any authenticated user with attachment access) and outbound webhook delivery (admin/API user). ## Credit Reported by tonghuaroot (tonghuaroot@gmail.com).

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • composer espocrm/espocrm<= 10.0.3

How to fix CVE-2026-88896

  • Upgrade

    CVE-2026-88896 lists a fix boundary at 10.0.3. Compare the installed build with that boundary before you change production.

  • Version check

    Affected <= 10.0.3

  • Advisory

    Open the cve_org record and follow its fix.

  • Official advisories

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-88896. EPSS is 0.37%. Act only if a listed version of SSRF via IPv6 transition is installed.

Which versions are affected?

Compare what you have installed with <= 10.0.3. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-918: Server-Side Request Forgery (SSRF). EPSS 0.37%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

EspoCRM security

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Aug 13, 2026 · Maintainer security tabs

    Detected

    ## Summary EspoCRM's validates outbound URLs to block requests to internal/private IP addresses. The check strips (IPv4-mapped IPv6) prefixes but does not recognize IPv6 transition addresses that embed private IPv4 addresses: NAT64 ( ), 6to4 ( ), and Teredo ( ). An attacker controlling a domain with AAAA DNS records pointing to these transition addresses can bypass both the host validation check a

  2. Sep 14, 2026 · Maintainer security tabs

    Updated

    ## Summary EspoCRM's validates outbound URLs to block requests to internal/private IP addresses. The check strips (IPv4-mapped IPv6) prefixes but does not recognize IPv6 transition addresses that embed private IPv4 addresses: NAT64 ( ), 6to4 ( ), and Teredo ( ). An attacker controlling a domain with AAAA DNS records pointing to these transition addresses can bypass both the host validation check a

Sources

  • CVE.orgVulnerability recordCVE-2026-88896

    Official CVE identifier

    cve.org
  • Maintainer security tabsVendor advisoryGHSA-xwmh-j8hf-cfqw

    ## Summary EspoCRM's validates outbound URLs to block requests to internal/private IP addresses. The check strips (IPv4-mapped IPv6) prefixes but does not recognize IPv6 transition addresses that embed private IPv4 addresses: NAT64 ( ), 6to4 ( ), and Teredo ( ). An attacker controlling a domain with AAAA DNS records pointing to these transition addresses can bypass both the host validation check a

    github.com

Freshness

Last verified in this catalog Nov 1, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • CVE.orgNov 2, 2026
  • Maintainer security tabsNov 1, 2026