CVE-2026-85221 MISP CurlClient TLS Peer Verification Disabled by Default Enables Man-in-the-Middle Attacks
Attackers can perform man-in-the-middle attacks on MISP HTTPS connections due to disabled TLS peer verification, exposing sensitive threat intelligence and credentials.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-85221?
CVE-2026-85221 is a high-severity vulnerability in Misp-Project Misp, published on 3 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
MISP contains an improper TLS certificate validation vulnerability in CurlClient. The CurlClient::$verifyPeer property was not explicitly initialized and therefore defaulted to null. When passed to cURL, this value effectively disabled TLS peer verification unless the calling code explicitly enabled it.
As a result, HTTPS connections made through affected CurlClient instances could accept certificates that were not issued by a trusted certificate authority. An attacker capable of intercepting or manipulating network traffic between a MISP instance and a remote HTTPS service could impersonate the remote endpoint and perform a man-in-the-middle attack.
Successful exploitation could allow an attacker to observe sensitive information transmitted by MISP, including authentication material or exchanged threat intelligence, and to modify responses returned to the MISP instance. The impact depends on the functionality using CurlClient and the data exchanged with the remote service.
The patch enables TLS peer verification by default while preserving explicit support for configured self-signed certificates. It also corrects the self-signed certificate handling in SyncTool so that peer verification is disabled only when no pinned CA certificate is configured.
Weakness: CWE-295
Which versions are affected by CVE-2026-85221?
It affects 1 product.
Products include Misp-Project Misp.
How do I fix CVE-2026-85221?
No fix has been published for CVE-2026-85221 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-85221 being exploited?
There is no known exploitation of CVE-2026-85221 in the wild and no public exploit code.
Other vulnerabilities in Misp-Project Misp
Sources
Also known as GHSA-37pq-fmvf-2fwx.