Vulnerability · Published Jul 23, 2026 · Assigned by AMZN

CVE-2026-16756Allocation of resources without limits in the default aws-smithy-http-server serve() path allows unauthenticated Slowloris denial of service

High 7.5

In plain English

A high-severity resource allocation without limits in aws-smithy-http-server from AWS. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.8% (higher than 55% of all known vulnerabilities).

Severity (CVSS 3.1)7.5High

Exploit odds (30 days)0.8%top 44.8% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

Missing connection and header-read timeouts and the absence of a concurrent-connection cap in the default serve() path of Amazon aws-smithy-http-server might allow remote attackers to cause a denial of service by opening many connections and sending partial requests that are never completed, exhausting server sockets and tasks. To mitigate this issue, users should upgrade to aws-smithy-http-server 0.66.5 or later.

Affected products (as reported)

Vendor	Product	Versions
AWS	aws-smithy-http-server	0 – through 0.66.4

Weakness: CWE-770 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

https://crates.io/crates/aws-smithy-http-server/0.66.5 release-notes, patch
https://aws.amazon.com/security/security-bulletins/2026-064-aws/ vendor-advisory
https://github.com/smithy-lang/smithy-rs/security/advisories/GHSA-jvxp-qmx7-gjpx release-notes