# RUSTSEC-2026-0339: Unbounded growth of pending connection ID retirements in quinn-proto > A remote attacker can cause unbounded memory growth in quinn-proto by flooding NEW_CONNECTION_ID frames, leading to denial of service. - **Severity:** Not scored - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 17 Aug 2026 - **Also known as:** GHSA-hmxj-32vh-65vr ## What is RUSTSEC-2026-0339? RUSTSEC-2026-0339 is a denial of service vulnerability in quinn-proto, published on 17 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description When processing a NEW_CONNECTION_ID frame, quinn-proto queues a RETIRE_CONNECTION_ID frame for each connection ID that the peer asked it to retire. The normal path bounds this queue and closes the connection with a CONNECTION_ID_LIMIT_ERROR if the bound would be exceeded. However, the path handling a connection ID that had already been retired pushed onto the queue without applying the limit and without deduplicating. A peer that has completed the handshake can first send a NEW_CONNECTION_ID frame with a large `retire_prior_to` value to advance the receiver's connection ID window, and then repeatedly send NEW_CONNECTION_ID frames with sequence numbers below that window. Each such frame adds another entry to the queue. The queue is only drained by sending RETIRE_CONNECTION_ID frames, which are subject to congestion control, so a peer that withholds acknowledgements can stall the drain while continuing to flood, growing the victim's memory use without bound. The flaw was corrected in 0.11.17 by applying the same limit on the already-retired path. Thanks to [@scadastrangelove](https://github.com/scadastrangelove) for reporting this issue. ## Which versions are affected by RUSTSEC-2026-0339? 1 open source package ship an affected version, including quinn-proto. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `quinn-proto` | crates.io | From 0.6.0 | 0.11.17 | ## How do I fix RUSTSEC-2026-0339? Upgrade quinn-proto to 0.11.17 or later. ## Is RUSTSEC-2026-0339 being exploited? There is no known exploitation of RUSTSEC-2026-0339 in the wild and no public exploit code. ## Fix prompt for AI coding agents ```text Check this codebase for RUSTSEC-2026-0339 and fix it if it is affected. What it is: RUSTSEC-2026-0339 is a denial of service vulnerability in quinn-proto, published on 17 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 RUSTSEC-2026-0339 in the wild and no public exploit code. Affected packages and fixed versions: - quinn-proto (crates.io): affected from 0.6.0; fixed in 0.11.17 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/RUSTSEC-2026-0339/ (Markdown: https://insights.sbomify.com/RUSTSEC-2026-0339/index.md) ``` ## Sources - OSV: https://osv.dev/vulnerability/RUSTSEC-2026-0339 --- From sbomify Insights: https://insights.sbomify.com/RUSTSEC-2026-0339/ Summaries are generated and may contain mistakes; the official description above is the record.