# CVE-2026-70464: rsync 2.0.0 < 3.5.0 Connection Slot Exhaustion DoS via Handshake Stall

> Unauthenticated attackers can exhaust rsync daemon connection slots by stalling handshakes, causing denial of service for legitimate clients.

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 13 Aug 2026
- **Updated:** 14 Aug 2026
- **Also known as:** ALPINE-CVE-2026-70464, AZL-95792, BELL-CVE-2026-70464, DEBIAN-CVE-2026-70464, ECHO-3879-0d40-e19e, GHSA-hrwq-ccf7-rw5m, ROOT-OS-DEBIAN-11-CVE-2026-70464, UBUNTU-CVE-2026-70464

## What is CVE-2026-70464?

CVE-2026-70464 is a high-severity denial of service vulnerability in RsyncProject rsync, published on 13 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

rsync daemon 2.0.0 before 3.5.0 contains a denial of service vulnerability that allows unauthenticated remote attackers to exhaust daemon connection slots by stalling the handshake process before or after module selection without triggering the I/O timeout. Attackers can open many simultaneous connections and trickle data at the minimum rate to avoid timeout, or stall entirely before module selection where no timeout applies, consuming all available connection slots and denying service to legitimate clients.

Weakness: CWE-770 (Allocation of Resources Without Limits or Throttling)

## Which versions are affected by CVE-2026-70464?


## How do I fix CVE-2026-70464?

Upgrade to a fixed version.

## Is CVE-2026-70464 being exploited?

There is no known exploitation of CVE-2026-70464 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-70464 and fix it if it is affected.

What it is: CVE-2026-70464 is a high-severity denial of service vulnerability in RsyncProject rsync, published on 13 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-70464 in the wild and no public exploit code.

Affected product: RsyncProject rsync. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-70464/ (Markdown: https://insights.sbomify.com/CVE-2026-70464/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-70464
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-70464
- OSV: https://osv.dev/vulnerability/CVE-2026-70464

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-70464/
Summaries are generated and may contain mistakes; the official description above is the record.