CVE-2026-45232: Off-by-one Error in RsyncProject rsync
An off-by-one out-of-bounds stack write vulnerability exists in rsync versions before 3. 4. 3 in the establish_proxy_connection() function. This flaw occurs when a malformed HTTP proxy response line of 1023 or more bytes without a newline terminator is processed while the RSYNC_PROXY environment variable is set. The vulnerability allows a network attacker positioned between the client and proxy or controlling the proxy to corrupt stack memory. The CVSS 4. 0 base score is 2. 1, indicating low severity. No official patch or remediation guidance is currently available. Exploitation in the wild is not known.
AI Analysis
Technical Summary
CVE-2026-45232 is an off-by-one error vulnerability in the RsyncProject's rsync software prior to version 3.4.3. The issue is located in the establish_proxy_connection() function within socket.c, where processing a malformed HTTP proxy response line of 1023 or more bytes without a newline terminator causes a null byte to be written out-of-bounds on the stack. This occurs only when the RSYNC_PROXY environment variable is set. An attacker who can intercept or control the proxy response can trigger this stack corruption. The vulnerability has a low CVSS 4.0 score of 2.1, reflecting limited impact and high attack complexity.
Potential Impact
The vulnerability allows an attacker to corrupt stack memory by sending a specially crafted HTTP proxy response. However, the low CVSS score and lack of known exploits suggest limited practical impact. There is no indication of privilege escalation, remote code execution, or denial of service beyond potential memory corruption. The attack requires network positioning between the client and proxy or control over the proxy server and the RSYNC_PROXY environment variable to be set.
Mitigation Recommendations
No official patch or remediation is currently available for this vulnerability. Users should monitor the RsyncProject advisories for updates and consider avoiding use of the RSYNC_PROXY environment variable or untrusted proxies until a fix is released. Patch status is not yet confirmed — check the vendor advisory for current remediation guidance.
CVE-2026-45232: Off-by-one Error in RsyncProject rsync
Description
An off-by-one out-of-bounds stack write vulnerability exists in rsync versions before 3. 4. 3 in the establish_proxy_connection() function. This flaw occurs when a malformed HTTP proxy response line of 1023 or more bytes without a newline terminator is processed while the RSYNC_PROXY environment variable is set. The vulnerability allows a network attacker positioned between the client and proxy or controlling the proxy to corrupt stack memory. The CVSS 4. 0 base score is 2. 1, indicating low severity. No official patch or remediation guidance is currently available. Exploitation in the wild is not known.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-45232 is an off-by-one error vulnerability in the RsyncProject's rsync software prior to version 3.4.3. The issue is located in the establish_proxy_connection() function within socket.c, where processing a malformed HTTP proxy response line of 1023 or more bytes without a newline terminator causes a null byte to be written out-of-bounds on the stack. This occurs only when the RSYNC_PROXY environment variable is set. An attacker who can intercept or control the proxy response can trigger this stack corruption. The vulnerability has a low CVSS 4.0 score of 2.1, reflecting limited impact and high attack complexity.
Potential Impact
The vulnerability allows an attacker to corrupt stack memory by sending a specially crafted HTTP proxy response. However, the low CVSS score and lack of known exploits suggest limited practical impact. There is no indication of privilege escalation, remote code execution, or denial of service beyond potential memory corruption. The attack requires network positioning between the client and proxy or control over the proxy server and the RSYNC_PROXY environment variable to be set.
Mitigation Recommendations
No official patch or remediation is currently available for this vulnerability. Users should monitor the RsyncProject advisories for updates and consider avoiding use of the RSYNC_PROXY environment variable or untrusted proxies until a fix is released. Patch status is not yet confirmed — check the vendor advisory for current remediation guidance.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- VulnCheck
- Date Reserved
- 2026-05-11T14:14:49.612Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a0d0f6cba1db473621796e9
Added to database: 5/20/2026, 1:33:32 AM
Last enriched: 5/20/2026, 1:48:40 AM
Last updated: 5/20/2026, 5:26:13 PM
Views: 9
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