Sources: National Vulnerability Database, CVE.org, CISA KEV, FIRST EPSS
CVE-2026-121451 Overview
AB Download Manager before 1.11.2 contains a cross-site request forgery vulnerability in its unauthenticated browser-integration API that allows remote attackers to write attacker-chosen files to arbitrary paths. A malicious web page can send a text/plain request to /start-headless-download with crafted folder and name values, placing payloads in startup folders for code execution on next login.
Critical Impact
Affected Products
- AB Download Manager: see the vendor advisory for the exact affected versions
Discovery Timeline
- 2026-11-03: CVE-2026-121451 published to the National Vulnerability Database by disclosure@vulncheck.com
- 2026-11-03: last updated in the NVD database
Technical Details for CVE-2026-121451
Vulnerability Analysis
CVE-2026-121451 is a Cross Site Request Forgery weakness (CWE-352: Cross Site Request Forgery) in AB Download Manager. Based on its CVSS vector, the flaw can be reached over the network, needs no login, and relies on a user taking an action. A logged in user's browser can be tricked into sending unwanted requests.
With a CVSS base score of 8.7, apply the vendor fix and confirm exposure on internet facing and business critical assets first.
Root Cause
The weakness is classified as CWE-352: Cross Site Request Forgery. A logged in user's browser can be tricked into sending unwanted requests.
Attack Vector
Based on the CVSS vector, the flaw can be reached over the network, needs no login, and relies on a user taking an action. Attack complexity is low complexity.
No exploitation in the wild is confirmed by CISA at the time of the last update. Check the references below for any vendor or researcher proof of concept.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Detection Methods for CVE-2026-121451
Detection Strategies
- Inventory every instance of AB Download Manager and compare the running version with the affected range above.
- Check external attack surface scans for internet facing instances of the component.
- Run an authenticated vulnerability scan once your scanner ships a check for this CVE.
Monitoring Recommendations
- Forward AB Download Manager application, access and audit logs to your SIEM for retrospective hunting.
- Alert on new processes, configuration changes or outbound connections from the affected service.
- Track the vendor advisory and the CISA KEV catalog for changes in exploitation status.
How to Mitigate CVE-2026-121451
Immediate Actions Required
- Apply the fixed version of AB Download Manager named in the vendor advisory.
- Prioritize internet facing and business critical instances first.
- Rescan after the change to confirm the exposure is closed.
Patch Information
Use the fixed version listed in the vendor advisory for AB Download Manager.
Workarounds
- If patching must wait, restrict network access to the affected service and place it behind authentication or a web application firewall rule.
CWE References
- CWE-352: Cross Site Request Forgery More CVEs with this weakness
Technical References
This entry is built directly from NVD, CISA KEV and EPSS data. Verify fixed versions in the vendor advisory before you deploy.
Frequently asked questions
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