CVE-2026-48440: Adobe ColdFusion Buffer Overflow Flaw

CVE-2026-48440 Overview

CVE-2026-48440 is a heap-based buffer overflow vulnerability affecting Adobe ColdFusion 2023 and 2025. The flaw allows an unauthenticated network attacker to trigger arbitrary code execution in the context of the current user running the ColdFusion service. Exploitation does not require user interaction, though success depends on conditions outside the attacker's direct control. The weakness is classified under [CWE-122] Heap-based Buffer Overflow. Adobe published the security advisory APSB26-90 documenting the fix.

Critical Impact
An unauthenticated attacker who successfully exploits this heap corruption can execute arbitrary code on the ColdFusion server, leading to full application compromise, data theft, and lateral movement.

Affected Products

Adobe ColdFusion 2023 (base release through Update 22)
Adobe ColdFusion 2025 (base release through Update 11)
ColdFusion deployments on any supported operating system running the affected updates

Discovery Timeline

2026-08-11 - CVE-2026-48440 published to NVD
2026-08-13 - Last updated in NVD database

Technical Details for CVE-2026-48440

Vulnerability Analysis

The vulnerability is a heap-based buffer overflow in Adobe ColdFusion. Heap overflows occur when a process writes data beyond the boundary of a dynamically allocated buffer, corrupting adjacent heap metadata or object pointers. In ColdFusion, an attacker can send crafted input over the network to trigger the overflow condition. Successful memory corruption enables the attacker to overwrite control-flow structures and hijack execution. Because ColdFusion runs as a Java-based application server, the resulting code execution occurs in the context of the service account hosting the ColdFusion runtime. The advisory notes the attack complexity is high, meaning exploitation depends on runtime conditions the attacker cannot fully control. The EPSS probability is 0.618% as of 2026-08-13.

Root Cause

The root cause is insufficient bounds checking on attacker-supplied data before it is written into a heap-allocated buffer. When the input size exceeds the buffer capacity, the write operation corrupts adjacent heap chunks. Adobe has not published the exact affected component or parser, but the classification under [CWE-122] confirms improper heap boundary enforcement during data processing.

Attack Vector

The attack vector is network-based and requires no authentication or user interaction. An attacker sends a specially crafted request to a reachable ColdFusion endpoint. Because exploitation depends on memory layout and timing conditions, the attack is probabilistic rather than deterministic. Servers exposed to the public internet or accessible from untrusted network segments face the highest risk. Refer to the Adobe ColdFusion Security Advisory for vendor-supplied technical context.

Detection Methods for CVE-2026-48440

Indicators of Compromise

Unexpected coldfusion.exe or JVM child processes spawning shells, cmd.exe, powershell.exe, or /bin/sh from the ColdFusion service account
ColdFusion service crashes, JVM heap corruption exceptions, or repeated restarts in coldfusion-out.log and coldfusion-error.log
Anomalous outbound network connections originating from the ColdFusion server to unknown IP addresses
New or modified .cfm, .cfc, or .jsp files under the ColdFusion webroot outside of normal deployment windows

Detection Strategies

Monitor ColdFusion process behavior for child process creation, file writes to webroot directories, and unexpected network egress
Deploy web application firewall rules that inspect request bodies and headers for oversized or malformed payloads targeting ColdFusion endpoints
Correlate JVM crash signatures with inbound HTTP request patterns to identify probing attempts
Alert on failed exploitation attempts that produce heap corruption stack traces in ColdFusion logs

Monitoring Recommendations

Ingest ColdFusion application, access, and error logs into a centralized SIEM for behavioral analysis
Track authentication events and administrative actions performed by the ColdFusion service account
Baseline normal outbound traffic from ColdFusion hosts and alert on deviations
Review scheduled tasks, new user accounts, and startup entries on ColdFusion servers on a recurring basis

How to Mitigate CVE-2026-48440

Immediate Actions Required

Apply the Adobe security update referenced in APSB26-90 to all ColdFusion 2023 and 2025 installations
Restrict network access to ColdFusion administrator and application endpoints using firewalls and reverse proxies
Run the ColdFusion service under a least-privilege account rather than SYSTEM, root, or a domain administrator
Audit ColdFusion servers for signs of prior exploitation before and after patching

Patch Information

Adobe has released fixed builds for both ColdFusion 2023 and ColdFusion 2025. Administrators should follow the guidance in the Adobe ColdFusion Security Advisory to install the current update level for their major version. Verify the patch level using the ColdFusion Administrator console after installation.

Workarounds

Place ColdFusion behind a hardened reverse proxy or web application firewall that enforces strict request size and content-type validation
Disable or remove unused ColdFusion components, sample applications, and administrative endpoints exposed to untrusted networks
Enforce network segmentation so ColdFusion servers cannot initiate arbitrary outbound connections

bash

# Configuration example: restrict ColdFusion Administrator access to trusted management network
# Example iptables rules on a Linux ColdFusion host
iptables -A INPUT -p tcp --dport 8500 -s 10.0.10.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 8500 -j DROP

# Verify running ColdFusion version and update level
cd /opt/coldfusion2025/cfusion/bin
./coldfusion status