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Findings

Vulnerability · RUSTSEC-2026-0339

Unbounded growth of pending connection ID retirements in quinn-proto

Published Aug 17, 2026 · RustSec Rust · evidence confidence high

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 value to advance the receiver's connection ID window, and then repeatedly send NEW_C

Grounded briefings

Catalog interpretations for three audiences. Each brief cites ingested metadata and the original advisories below. They are not independent research and they do not invent exploit steps.

Executive

RUSTSEC-2026-0339 is a unknown public vulnerability record for RustSec Rust. It is not currently listed in the CISA Known Exploited catalog. Check the linked vendor or CERT advisories for patch status. This summary is a catalog interpretation of the ingested metadata and cites the original advisories below.

System administrator

Identify whether RustSec Rust is in your estate, then compare installed versions with the affected ranges. Affected version ranges have not been ingested yet. Check the linked vendor or CERT advisories for patch status. Prefer the vendor or distribution advisory linked in Sources before changing production systems. This is a catalog interpretation, not a runbook.

Security analyst

Signals on file: no CVSS/EPSS yet. It is not currently listed in the CISA Known Exploited catalog. Sources contributing to this record: rustsec. Public exploit references, when present, are outbound links only and are not proof of active exploitation. This is a catalog interpretation of stored metadata.

Exploitation and remediation

  • Exploitation evidence

    Not listed as known exploited in CISA KEV. Not in CISA KEV or VulnCheck KEV.

  • Patch and remediation

    No required-action text is stored yet. Use the vendor or CERT links in Sources for patch availability.

  • Safe detection guidance

    Compare installed versions with the affected ranges below and verify the advisory from the original publisher. This site stores metadata and outbound links only; it does not ship exploit code or proof-of-concept payloads.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Aug 17, 2026 · RustSec Advisory DB

    Detected

    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 w

Sources

  • RustSec Advisory DBVendor advisoryRUSTSEC-2026-0339

    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

    crates.io