Vulnerability HighRUSTSEC-2026-0340 · quinn-proto
RUSTSEC-2026-0340: Peer minimum ACK delay can panic quinn-proto when ACK_FREQUENCY transmission is enabled
Short answerA security vulnerability in the quinn-proto crate: Peer minimum ACK delay can panic quinn-proto when ACK_FREQUENCY transmission is enabled. High severity (CVSS 7.5). Fixed in 0.11.18: update to a fixed version.
| Crate | quinn-proto |
|---|---|
| Type | Vulnerability (denial-of-service) |
| Affected versions | From 0.11.0 before 0.11.18. |
| Fixed in | 0.11.18 |
| Severity | High, CVSS 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| Published | 2026-09-14 |
| Last changed | 2026-10-12 |
| Also known as | GHSA-3g6h-r5qx-f6hq |
What to do
- See which version you have:
cargo tree -i quinn-proto(it also shows which of your dependencies pulls it in). - Update within your version requirement:
cargo update -p quinn-proto. If the fix is a newer major or minor than your requirement allows, raise it in Cargo.toml (for examplequinn-proto = "0.11.18") or update the dependency that pulls it in. - Check again with
cargo audit, or paste your Cargo.lock into our Cargo.toml checker.
Details from the advisory
When sending ACK_FREQUENCY frames is enabled through TransportConfig::ack_frequency_config(Some(..)), the peer's transport parameters could cause AckFrequencyState::candidate_max_ack_delay to call Duration::clamp with a minimum greater than its maximum, which panics.
For example, a peer advertising a min_ack_delay of 100,000 microseconds and a max_ack_delay of 100 milliseconds passes transport parameter validation. At a 5 ms RTT, the lower bound of the clamp becomes 100 ms while the upper bound is 25 ms, violating the precondition of clamp and panicking while driving the connection. Both automatically derived and explicitly configured maximum ACK delays use this calculation.
Sending ACK_FREQUENCY frames is disabled by default, so only endpoints that opt in are affected.
The flaw was corrected in 0.11.18 by computing the delay with explicit minimum and maximum bounds instead of clamp.
Thanks to @zerox80 for reporting this issue.
References
- Package: crates.io/crates/quinn-proto
- Advisory: rustsec.org/advisories/RUSTSEC-2026-0340.html
- Web: github.com/quinn-rs/quinn/pull/2868
From the RustSec Advisory Database (CC0-1.0) via the OSV export, downloaded Oct 24, 2026. Severity score computed from the published CVSS vector.
Other advisories for quinn-proto
- Vulnerability HighRUSTSEC-2023-0063 · 2023-09-21Denial of service in Quinn servers
- Vulnerability HighRUSTSEC-2024-0373 · 2024-09-02`Endpoint::retry()` calls can lead to panicking
- VulnerabilityRUSTSEC-2026-0037 · 2026-03-09Denial of service in Quinn endpoints
- Vulnerability HighRUSTSEC-2026-0185 · 2026-06-22 Remote memory exhaustion in quinn-proto from unbounded out-of-order stream reassembly
- VulnerabilityRUSTSEC-2026-0338 · 2026-09-14Remote peer can panic quinn-proto with zero-length STREAM frames during unordered reads
- VulnerabilityRUSTSEC-2026-0339 · 2026-08-17Unbounded growth of pending connection ID retirements in quinn-proto
- Vulnerability HighRUSTSEC-2026-0341 · 2026-08-17Stream reassembly memory-exhaustion guard in quinn-proto can be bypassed
- VulnerabilityRUSTSEC-2026-0342 · 2026-08-17Zero-length DATAGRAM frames bypass the receive buffer limit in quinn-proto
Up next
Same cratequinn-proto: security historyEvery advisory for this crate, and whether it is safe to use today.Read it next →Did this answer your question?