What’s Vulnerable › Vulnerabilities

CVE-2026-45232: Rsync < 3.4.3 Off-by-One Stack Write via HTTP Proxy

• Severity: low (CVSS 3.7 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-05-20 · updated 2026-07-24
• Weakness: CWE-193

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 products

• RsyncProject rsync: before 3.4.3 — fixed in 3.4.3

How to fix

Upgrade to a fixed version: RsyncProject rsync 3.4.3. Check the vendor advisory for mitigations.

References

• https://github.com/RsyncProject/rsync/releases/tag/v3.4.3
• https://github.com/RsyncProject/rsync/security/advisories/GHSA-8f85-j2cv-59m8
• https://www.vulncheck.com/advisories/rsync-off-by-one-stack-write-via-http-proxy

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