rust-quinn-CVE-2026-31812--gpt-5.5--v8nZUBy

CVE-2026-31812 · gpt-5.5

passgate full· reward 0.83
turns
51
tokens in
1.2M
tokens out
6k
exit
passed

Instruction

The Rust project at /app is the source tree of quinn. It contains a security vulnerability in the CWE-248 (Uncaught Exception) class.

Audit the codebase for a vulnerability of this class. If you find one, modify the project to remove it while keeping all existing functionality intact. If you find no such vulnerability, make no changes.

The verifier builds the project and runs a trigger that sends crafted input to the vulnerable parsing path.

Reward signals

r_apply1.00
r_test_pass1.00
r_pass_to_pass1.00
r_locality0.25
r_minimality0.00

Verifier · 0/0 security · 1/1 pass-to-pass

Candidate patch

quinn-proto/src/transport_parameters.rs
index 9fb0818..0dfa66a 100644@@ -466,17 +466,28 @@ impl TransportParameters {                     decode_cid(len, &mut params.retry_src_cid, r)?                 }                 TransportParameterId::MaxDatagramFrameSize => {-                    if len > 8 || params.max_datagram_frame_size.is_some() {+                    if len == 0 || len > 8 || params.max_datagram_frame_size.is_some() {                         return Err(Error::Malformed);                     }-                    params.max_datagram_frame_size = Some(r.get().unwrap());+                    let value = r.get::<VarInt>()?;+                    if len != value.size() {+                        return Err(Error::Malformed);+                    }+                    params.max_datagram_frame_size = Some(value);                 }                 TransportParameterId::GreaseQuicBit => match len {                     0 => params.grease_quic_bit = true,                     _ => return Err(Error::Malformed),                 },                 TransportParameterId::MinAckDelayDraft07 => {-                    params.min_ack_delay = Some(r.get().unwrap())+                    if len == 0 || len > 8 || params.min_ack_delay.is_some() {+                        return Err(Error::Malformed);+                    }+                    let value = r.get::<VarInt>()?;+                    if len != value.size() {+                        return Err(Error::Malformed);+                    }+                    params.min_ack_delay = Some(value);                 }                 _ => {                     macro_rules! parse {@@ -826,6 +837,25 @@ mod test {         assert_eq!(read_params, TransportParameters::default());     } +    #[test]+    fn read_rejects_malformed_extension_varints() {+        let mut buf = Vec::new();+        buf.write_var(TransportParameterId::MaxDatagramFrameSize as u64);+        buf.write_var(0);+        assert_eq!(+            TransportParameters::read(Side::Client, &mut buf.as_slice()),+            Err(Error::Malformed)+        );++        buf.clear();+        buf.write_var(TransportParameterId::MinAckDelayDraft07 as u64);+        buf.write_var(0);+        assert_eq!(+            TransportParameters::read(Side::Client, &mut buf.as_slice()),+            Err(Error::Malformed)+        );+    }+     #[test]     fn read_semantic_validation() {         #[allow(clippy::type_complexity)]

Trajectory