CVE-2026-43618: Rsync < 3.4.3 Integer Overflow Information Disclosure
A flaw was found in rsync. An authenticated daemon peer can exploit an integer overflow vulnerability in the compressed-token decoder. By carefully manipulating the compressed-token, a malicious sender can trigger an overflow, leading to remote memory disclosure. This allows an attacker to leak sensitive process memory contents, including environment variables, passwords, and memory pointers, which significantly weakens Address Space Layout Randomization (ASLR) and can facilitate further exploitation.
Other sources
Rsync < 3.4.3 Integer Overflow Information Disclosure
— Microsoft
Rsync version 3.4.2 and prior contain an integer overflow vulnerability in the compressed-token decoder where a 32-bit signed counter is not checked for overflow, allowing a malicious sender to trigger an overflow that causes the receiver process to read and return data from outside the intended buffer bounds. Attackers can exploit this vulnerability to disclose process memory contents including environment variables, passwords, heap and stack data, and library memory pointers, significantly reducing ASLR effectiveness and facilitating further exploitation.
— Launchpad
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
debian/rsyncto a version that resolves this vulnerability.Fixed in 3.2.3-4+deb11u4Fixed in 3.2.7-1+deb12u5Fixed in 3.4.1+ds1-5+deb13u3Fixed in 3.4.3+ds1-2 - Upgrade
Upgrade
rsyncto a version that resolves this vulnerability.Fixed in 3.4.3Patch CVE-2026-29518 - Upgrade
Upgrade
rsyncto a version that resolves this vulnerability.Fixed in 3.4.3Patch CVE-2026-43617 - Upgrade
Upgrade
rsyncto a version that resolves this vulnerability.Fixed in 3.4.3Patch CVE-2026-43618 - Upgrade
Upgrade
rsyncto a version that resolves this vulnerability.Fixed in 3.4.3Patch CVE-2026-43619 - Upgrade
Upgrade
rsyncto a version that resolves this vulnerability.Fixed in 3.4.3Patch CVE-2026-43620 - Upgrade
Upgrade
rsyncto a version that resolves this vulnerability.Fixed in 3.4.3Patch CVE-2026-45232 - Compensating control
Ensure the rsync daemon is not exposed to untrusted networks; only allow authenticated, trusted peers to connect to the rsync daemon.
Event History
Frequently Asked Questions
What is the severity of CVE-2026-43618?
The severity of CVE-2026-43618 is classified as high due to the potential for information disclosure through an integer overflow.
How do I fix CVE-2026-43618?
To fix CVE-2026-43618, upgrade Rsync to version 3.4.3 or later.
What systems are affected by CVE-2026-43618?
CVE-2026-43618 affects Rsync versions prior to 3.4.3, specifically 3.4.2 and earlier.
What is the impact of exploiting CVE-2026-43618?
Exploiting CVE-2026-43618 can allow a malicious sender to trigger an integer overflow, leading to potential information disclosure.
Is CVE-2026-43618 present in any commonly used distributions?
Yes, CVE-2026-43618 may be present in various Linux distributions that include affected versions of Rsync.