CVE-2026-86419: MISP Insufficient Outbound URL Validation Allows SSRF and Credential Disclosure via Feed Redirects and TAXII Discovery
Affected versions of MISP contain insufficient validation of server-side outbound HTTP destinations in feed retrieval and TAXII discovery functionality.
In feed processing, redirects were followed without validating the redirect scheme or destination. The original request headers were reused across redirect hops, meaning authentication headers or API credentials configured for a feed could be forwarded to a different host. Redirects could also target internal network resources, resulting in SSRF. The fix adds redirect validation, blocks internal destinations for cross-host redirects, strips configured feed credentials before following redirects to another host, and pins validated DNS results to prevent re-resolution after validation.
The TAXII discovery endpoint had a related incomplete SSRF defense. It used gethostbyname() and compared the result against only a few literal addresses. This missed cases including IPv6 loopback (::1), numeric host encodings such as 0x7f000001, and potentially multiple DNS records. The fix moves TAXII discovery to the shared URL egress validator.
Together, these commits harden MISP's outbound URL handling against alternate-address representations, DNS-related bypasses, unsafe redirects, internal-host access, and cross-host credential forwarding.
Version affected: ≤2.5.45
Affected Software
Event History
Frequently Asked Questions
Which deployments are most exposed to credential disclosure?
MISP deployments that retrieve feeds configured with authentication headers or API credentials are exposed if a feed can redirect requests to a different host. Before the fix, those original request headers were reused on redirect hops and could be sent to the redirected destination.
What redirect targets could be used for server-side request forgery?
A feed redirect could target internal network resources because the redirect destination and scheme were not adequately validated. The TAXII discovery handling also missed IPv6 loopback, numeric host encodings such as 0x7f000001, and cases involving multiple DNS records.
What conditions are needed to exploit the feed-related issue?
The issue depends on MISP retrieving a feed whose response causes a redirect. Credential disclosure additionally requires that the feed be configured with authentication headers or API credentials.
What protections were added by the fix?
The fix validates redirects, blocks internal destinations for cross-host redirects, and removes configured feed credentials before following a redirect to another host. It also pins validated DNS results to prevent re-resolution after validation and moves TAXII discovery to the shared URL egress validator.