CVE-2026-43618
Integer Overflow in Rsync Leading to Memory Disclosure
Publication date: 2026-05-20
Last updated on: 2026-05-20
Assigner: VulnCheck
Description
Description
CVSS Scores
EPSS Scores
| Probability: | |
| Percentile: |
Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| rsync | rsync | to 3.4.3 (exc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-125 | The product reads data past the end, or before the beginning, of the intended buffer. |
| CWE-190 | The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
CVE-2026-43618 is an integer overflow vulnerability in rsync versions prior to 3.4.3, specifically in the compressed-token decoder. The problem arises because a 32-bit signed counter is incremented without proper overflow checks. A malicious sender can exploit this flaw to trigger an overflow, causing the receiver process to read and return data from outside the intended buffer bounds.
This unintended memory read can disclose sensitive process memory contents such as environment variables, passwords, heap and stack data, and library memory pointers.
The vulnerability reduces the effectiveness of Address Space Layout Randomization (ASLR), which is a security technique used to prevent exploitation, thereby facilitating further attacks.
How can this vulnerability impact me? :
Exploitation of this vulnerability can lead to disclosure of sensitive information from the affected system's memory, including environment variables, passwords, and memory pointers.
This information leakage significantly weakens security defenses such as ASLR, making it easier for attackers to carry out further exploits.
The vulnerability impacts confidentiality by exposing sensitive data, and it also affects availability and integrity as indicated by the CVSS score.
How can this vulnerability be detected on my network or system? Can you suggest some commands?
This vulnerability affects rsync versions prior to 3.4.3. To detect if your system is vulnerable, you can check the installed rsync version.
- Run the command: rsync --version
If the version is 3.4.2 or earlier, your system is vulnerable to CVE-2026-43618.
Additionally, monitoring network traffic for rsync sessions that use compression might help identify potential exploitation attempts, since the vulnerability is in the compressed-token decoder.
What immediate steps should I take to mitigate this vulnerability?
The primary mitigation is to upgrade rsync to version 3.4.3 or later, where this vulnerability has been patched.
If upgrading immediately is not possible, a recommended workaround is to disable compression in the rsync daemon configuration to prevent exploitation of the compressed-token decoder.
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
This vulnerability allows attackers to disclose sensitive process memory contents including environment variables, passwords, and other memory data. Such unauthorized disclosure of sensitive information can lead to violations of data protection regulations like GDPR and HIPAA, which mandate the protection of personal and sensitive data.
By significantly reducing the effectiveness of Address Space Layout Randomization (ASLR) and facilitating further exploitation, this vulnerability increases the risk of data breaches and unauthorized access, which are critical compliance concerns under these standards.