Progress MarkLogic Server: Insufficient isolation of user-supplied code

Summary

Progress MarkLogic Server 11.x before 11.3.7 and 12.x before 12.1.0 do not sufficiently isolate user-supplied code run through certain REST and XDBC evaluation paths from HTTP request, response and session state. An attacker who can execute code through an affected path could perform unauthorized actions or compromise an authenticated session. The CVSS score is 9.6 (critical), but the vendor's preconditions, including whether a valid login is required, are not yet confirmed.

Affected

• MarkLogic Server 11.0.0 to before 11.3.7 (CVE record)
• MarkLogic Server 12.0.0 to before 12.1.0 (CVE record)
• Secondary reports list 11.0 to 11.3.6 and 12.0 to 12.0.3; verify with the vendor bulletin
• Releases 10.x and older are not covered by this fix; affected status unconfirmed

Fixed in

• Upgrade to 12.1.0 or 11.3.7 (per vendor bulletin)
• Releases 10.x and older are not patched; migration required

Workaround

• No vendor-published workaround found.
• Secondary guidance: place MarkLogic in segmented network zones and limit access to trusted sources.
• Restrict eval/XDBC privileges to accounts that need them and restrict access to the HTTP app-server ports.

Exploitation

• No known exploitation in the wild as of the research date; CISA KEV: no.
• CISA SSVC: exploitation none, automatable no, technical impact total.
• No public PoC according to TheHackerWire (secondary source, unverified).

Our recommendation

• Check whether MarkLogic is in use, including dev and test instances.
• Identify versions and upgrade to 11.3.7 or 12.1.0; plan migration for 10.x and older.
• Ensure the HTTP and XDBC app-server ports are not reachable from the internet.
• Review eval/XDBC privileges and admin accounts; check logs for unusual eval-endpoint activity.
• Before upgrading, test custom code that uses request or session functions from eval endpoints, as these now fail under isolation.
• Apply the full October 2026 bulletin, as it contains further critical flaws.

Public exploits iAttack code is publicly available (PoC on GitHub, Metasploit or Exploit-DB).

PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.

Research sources

• Progress MarkLogic Critical Security Alert Bulletin, October 2026 community.progress.com
• Strix CVE-2026-9191 www.strix.ai
• DEV Community: MarkLogic privilege escalation chain (affected version ranges) dev.to
• DEV Community: MarkLogic discloses 31 flaws, five rated critical dev.to
• TheHackerWire: CVE-2026-9191 code isolation bypass www.thehackerwire.com
• TheHackerWire: CVE-2026-9191 vulnerability entry www.thehackerwire.com
• GBHackers: Critical Progress MarkLogic Server vulnerabilities gbhackers.com

Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 30 Oct 2026, 23:05.