CVE-2021-47969 Overview
CVE-2021-47969 is a denial of service vulnerability affecting Color Notes version 1.4. Attackers can crash the application by pasting excessively long character strings into note input fields. A payload of 350,000 repeated characters, pasted twice into a new note, causes the application to stop responding. The flaw is categorized under [CWE-789: Memory Allocation with Excessive Size Value]. No authentication or user interaction beyond the paste action is required to trigger the condition.
Critical Impact
Attackers can render Color Notes 1.4 unresponsive by submitting oversized input strings, resulting in availability loss for affected users.
Affected Products
- Color Notes 1.4
- Earlier versions accepting unbounded input in note fields may also be affected
- No vendor-confirmed CPE entries are listed in NVD
Discovery Timeline
- 2026-05-16 - CVE-2021-47969 published to the National Vulnerability Database (NVD)
- 2026-05-18 - Last updated in NVD database
Technical Details for CVE-2021-47969
Vulnerability Analysis
The vulnerability is a denial of service condition triggered by improper handling of large input strings in Color Notes 1.4. The application accepts user input into note fields without enforcing size limits or validating allocation boundaries. When an attacker pastes a string of 350,000 repeated characters twice into a new note, the application consumes excessive memory or processing resources and stops responding.
The defect maps to [CWE-789: Memory Allocation with Excessive Size Value]. Applications that allocate memory based on user-controlled length values without sanity checks are exposed to exhaustion attacks. The exploit does not require privileges, authentication, or complex setup. Detailed reproduction steps are documented in the Exploit-DB #49952 entry and the VulnCheck advisory.
Root Cause
Color Notes 1.4 fails to validate the length of input strings written into note fields. The application does not truncate, reject, or stream oversized text. This allows a single user action to allocate or process memory blocks far exceeding reasonable note sizes, exhausting application resources.
Attack Vector
The attack vector is network-adjacent through any channel that can deliver a long string to the input field, including clipboard content shared from a remote source or scripted automation. An attacker provides a payload containing 350,000 repeated characters and pastes it twice into a new note. The application freezes and no longer responds to user input.
The vulnerability mechanism is described in prose only; no verified exploit code is reproduced here. See the Exploit-DB #49952 entry for the public proof of concept.
Detection Methods for CVE-2021-47969
Indicators of Compromise
- Color Notes application becoming unresponsive or terminating shortly after a paste operation in a note field
- Process memory growth spikes for Color Notes followed by hangs or crashes
- Crash logs or operating system error reports referencing Color Notes 1.4 with out-of-memory or unresponsive-application states
Detection Strategies
- Monitor endpoint telemetry for abnormal memory consumption tied to the Color Notes process
- Inspect application crash dumps for input handlers processing strings exceeding expected note length
- Correlate user-reported application hangs with recent paste activity from external clipboard sources
Monitoring Recommendations
- Track process resource utilization for Color Notes and alert on sustained memory growth above baseline
- Log and review repeated application restarts on endpoints running Color Notes 1.4
- Centralize endpoint crash reports to identify clusters of users hitting the same failure mode
How to Mitigate CVE-2021-47969
Immediate Actions Required
- Inventory endpoints running Color Notes 1.4 and prioritize upgrade or removal
- Restrict use of Color Notes 1.4 for handling untrusted content until a fixed version is confirmed
- Educate users to avoid pasting content from untrusted sources into the application
Patch Information
No vendor patch reference is listed in the NVD data for CVE-2021-47969. Consult the VulnCheck advisory and the Exploit-DB #49952 entry for the latest vendor response. If the vendor releases a fixed build, upgrade all Color Notes installations to that version.
Workarounds
- Avoid pasting large or untrusted strings into Color Notes 1.4 note fields
- Replace Color Notes 1.4 with an alternative note application that enforces input length limits
- Where feasible, apply application-layer controls that cap clipboard payload size before it reaches the application
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
