A Server-Side Request Forgery (SSRF) protection bypass existed in the html_to_markdown expansion module of misp-modules.
The module attempts to prevent requests to loopback, private, link-local, and other restricted IP address ranges. However, IP addresses were compared against the blocked ranges without first normalising IPv4-mapped IPv6 addresses.
An authenticated attacker able to invoke the module could supply an IPv4-mapped IPv6 address, such as:
http://[::ffff:127.0.0.1]/
http://[::ffff:169.254.169.254]/
Alternatively, the attacker could use a hostname that resolves to an IPv4-mapped IPv6 address. These addresses were treated as IPv6 addresses and therefore did not match the corresponding blocked IPv4 ranges.
Successful exploitation could cause the misp-modules server to connect to services available through its loopback interface, internal network, or link-local network. This could expose internal web services, administrative interfaces, or cloud instance metadata, with retrieved content potentially returned to the attacker as converted Markdown.
The vulnerability has been addressed by normalising IPv4-mapped IPv6 addresses to their underlying IPv4 representation before applying the blocked-range checks. URLs without a valid hostname are now also rejected.
SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.
An upstream fix is merged but not yet in a tagged release. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines until it ships, then apply the release.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.
In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it