CVE-2026-25800 quinn-rs CVE debrief

Who should care

Defenders responsible for deploying and managing quinn-proto should assess exposure to this vulnerability, especially in scenarios where untrusted peers may send unordered stream fragments. They should prioritize verifying the version of quinn-proto and implementing compensating controls to mitigate potential memory exhaustion.

Why it matters

CVE-2026-25800 is a remote memory exhaustion vulnerability in quinn-proto that can occur due to unbounded out-of-order stream reassembly. Defenders should prioritize verifying exposure and implementing compensating controls to mitigate potential memory exhaustion.

• Memory exhaustion can occur due to high buffer overhead
• Defenders must verify exposure in quinn-proto deployments
• Compensating controls are necessary to mitigate the risk

Technical summary

The `Assembler` component in quinn-proto incurs overhead for non-contiguous fragments when assembling unordered stream fragments into consecutive chunks. This can lead to high buffer overhead and memory exhaustion when readers read from a RecvStream in order and peers send fragments with many gaps. Defenders should prioritize verifying exposure in quinn-proto deployments, especially where untrusted peers may send unordered stream fragments. They should assess the impact of potential memory exhaustion and implement compensating controls to mitigate the risk.

Defensive priority

Defenders should prioritize verifying exposure in quinn-proto deployments, especially where untrusted peers may send unordered stream fragments. They should assess the impact of potential memory exhaustion and implement compensating controls to mitigate the risk.

Recommended defensive actions

• Verify quinn-proto version 0.11.15 or later is deployed
• Assess exposure to untrusted peers sending unordered stream fragments
• Implement compensating controls to mitigate potential memory exhaustion
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The vulnerability is described in the source item from osv_dev, which provides details about the `Assembler` component and its sensitivity to non-contiguous fragments. The CVE Program record and NVD vulnerability detail pages offer additional context.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.