CVE-2026-45232
Rsync < 3.4.3 Off-by-One Stack Write via HTTP Proxy
Description
Rsync versions before 3.4.3 contain an off-by-one out-of-bounds stack write vulnerability in the establish_proxy_connection() function in socket.c that allows network attackers to corrupt stack memory by sending a malformed HTTP proxy response. Attackers can exploit this by positioning themselves between the client and proxy or controlling the proxy server to send a response line of 1023 or more bytes without a newline terminator, causing a null byte to be written to an out-of-bounds stack address when the RSYNC_PROXY environment variable is set.
INFO
Published Date :
May 20, 2026, 2:16 a.m.
Last Modified :
July 24, 2026, 9:10 a.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | LOW | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 3.1 | LOW | [email protected] | ||||
| CVSS 3.1 | LOW | [email protected] | ||||
| CVSS 4.0 | LOW | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 4.0 | LOW | [email protected] |
Solution
- Update Rsync to version 3.4.3 or later.
- Apply vendor-provided security patches.
- Configure Rsync to not use the RSYNC_PROXY environment variable.
- Validate all Rsync configurations.
Public PoC/Exploit Available at Github
CVE-2026-45232 has a 1 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-45232.
| URL | Resource |
|---|---|
| https://github.com/RsyncProject/rsync/releases/tag/v3.4.3 | Release Notes |
| https://github.com/RsyncProject/rsync/security/advisories/GHSA-8f85-j2cv-59m8 | Vendor Advisory |
| https://www.vulncheck.com/advisories/rsync-off-by-one-stack-write-via-http-proxy | Third Party Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-45232 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-45232
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Classic rsync re-implementation in pure Rust
Rust Shell Python Ruby Makefile Dockerfile RenderScript C
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-45232 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-45232 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Translated by [email protected]
Jul. 24, 2026
Action Type Old Value New Value Added Translation Title: Rsync de RsyncProject, Description: Las versiones de Rsync anteriores a la 3.4.3 contienen una vulnerabilidad de escritura fuera de límites de la pila por un byte (off-by-one) en la función establish_proxy_connection() en socket.c que permite a los atacantes de red corromper la memoria de la pila enviando una respuesta de proxy HTTP malformada. Los atacantes pueden explotar esto posicionándose entre el cliente y el proxy o controlando el servidor proxy para enviar una línea de respuesta de 1023 o más bytes sin un terminador de nueva línea, causando que se escriba un byte nulo en una dirección de pila fuera de límites cuando la variable de entorno RSYNC_PROXY está configurada. -
CVE Modified by [email protected]
Jul. 14, 2026
Action Type Old Value New Value Changed Affected [{'repo': 'https://github.com/RsyncProject/rsync', 'vendor': 'RsyncProject', 'product': 'rsync', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '3.4.3', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}] [{'repo': 'https://github.com/RsyncProject/rsync', 'vendor': 'RsyncProject', 'product': 'rsync', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '3.4.3', 'versionType': 'semver'}], 'packageURL': 'pkg:github/RsyncProject/rsync', 'defaultStatus': 'unaffected'}] -
CVE Modified by [email protected]
Jun. 17, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://github.com/RsyncProject/rsync', 'vendor': 'RsyncProject', 'product': 'rsync', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '3.4.3', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}] -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 17, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-45232', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-05-20T17:30:10.337296Z'} -
Initial Analysis by [email protected]
May. 21, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L Added CPE Configuration OR *cpe:2.3:a:samba:rsync:*:*:*:*:*:*:*:* versions up to (excluding) 3.4.3 Added Reference Type VulnCheck: https://github.com/RsyncProject/rsync/releases/tag/v3.4.3 Types: Release Notes Added Reference Type VulnCheck: https://github.com/RsyncProject/rsync/security/advisories/GHSA-8f85-j2cv-59m8 Types: Vendor Advisory Added Reference Type VulnCheck: https://www.vulncheck.com/advisories/rsync-off-by-one-stack-write-via-http-proxy Types: Third Party Advisory -
New CVE Received by [email protected]
May. 20, 2026
Action Type Old Value New Value Added Description Rsync versions before 3.4.3 contain an off-by-one out-of-bounds stack write vulnerability in the establish_proxy_connection() function in socket.c that allows network attackers to corrupt stack memory by sending a malformed HTTP proxy response. Attackers can exploit this by positioning themselves between the client and proxy or controlling the proxy server to send a response line of 1023 or more bytes without a newline terminator, causing a null byte to be written to an out-of-bounds stack address when the RSYNC_PROXY environment variable is set. Added CVSS V4.0 AV:N/AC:H/AT:N/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CVSS V3.1 AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:L Added CWE CWE-193 Added Reference https://github.com/RsyncProject/rsync/releases/tag/v3.4.3 Added Reference https://github.com/RsyncProject/rsync/security/advisories/GHSA-8f85-j2cv-59m8 Added Reference https://www.vulncheck.com/advisories/rsync-off-by-one-stack-write-via-http-proxy