Vulnerability · Published May 20, 2026 · Assigned by VulnCheck
CVE-2026-45232Rsync < 3.4.3 Off-by-One Stack Write via HTTP Proxy
Low 3.1
In plain English
A low-severity security flaw in rsync from RsyncProject. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 27% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.20 | rsync | 3.4.3-r0 | ALPINE-CVE-2026-45232 |
| Alpine:v3.21 | rsync | 3.4.3-r0 | ALPINE-CVE-2026-45232 |
| Alpine:v3.22 | rsync | 3.4.3-r0 | ALPINE-CVE-2026-45232 |
| Alpine:v3.23 | rsync | 3.4.3-r0 | ALPINE-CVE-2026-45232 |
| Alpine:v3.24 | rsync | 3.4.3-r0 | ALPINE-CVE-2026-45232 |
| Debian:12 | rsync | 3.2.7-1+deb12u6 | DEBIAN-CVE-2026-45232 |
| Debian:13 | rsync | 3.4.1+ds1-5+deb13u4 | DEBIAN-CVE-2026-45232 |
| Debian:14 | rsync | 3.4.3+ds1-1 | DEBIAN-CVE-2026-45232 |
| Ubuntu:22.04:LTS | rsync | 3.2.7-0ubuntu0.22.04.6 | UBUNTU-CVE-2026-45232 |
| Ubuntu:24.04:LTS | rsync | 3.2.7-1ubuntu1.4 | UBUNTU-CVE-2026-45232 |
| Ubuntu:25.10 | rsync | 3.4.1+ds1-5ubuntu1.2 | UBUNTU-CVE-2026-45232 |
| Ubuntu:26.04:LTS | rsync | 3.4.1+ds1-7ubuntu0.2 | UBUNTU-CVE-2026-45232 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| RsyncProject | rsync | 0 – before 3.4.3 |
Weakness: CWE-193 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:L