Sources: National Vulnerability Database, CVE.org, CISA KEV, FIRST EPSS
CVE-2026-120436 Overview
Netpbm before 10.86.51, 11.x before 11.02.30, and 11.03 before 11.15.08 contains an integer overflow in jbigtopnm that causes heap buffer overflow when computing output buffer size. Attackers can supply a crafted multi-plane JBIG file with large header dimensions so jbg_dec_merge_planes() overflows the undersized buffer, causing crashes or potentially code execution.
Critical Impact
Affected Products
- Netpbm: see the vendor advisory for the exact affected versions
Discovery Timeline
- 2026-11-02: CVE-2026-120436 published to the National Vulnerability Database by disclosure@vulncheck.com
- 2026-11-02: last updated in the NVD database
Technical Details for CVE-2026-120436
Vulnerability Analysis
CVE-2026-120436 is a Integer Overflow weakness (CWE-190: Integer Overflow) in Netpbm. Based on its CVSS vector, the flaw needs local or adjacent access, needs no login, and relies on a user taking an action. A number wraps around and leads to wrong size calculations.
With a CVSS base score of 8.5, apply the vendor fix and confirm exposure on internet facing and business critical assets first.
Root Cause
The weakness is classified as CWE-190: Integer Overflow. A number wraps around and leads to wrong size calculations.
Attack Vector
Based on the CVSS vector, the flaw needs local or adjacent access, 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:L/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-2026-120436
Detection Strategies
- Inventory every instance of Netpbm 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 Netpbm 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-2026-120436
Immediate Actions Required
- Apply the fixed version of Netpbm 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 Netpbm.
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-190: Integer Overflow 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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