Vulnerability details

CVE-2026-16756

AWS aws-smithy-http-server

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

CVSS 4.0

8.7High

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.

CVSS scores

Score	Version	Source	Vector
8.7High	4.0	CVEProject cvelistV5 (CNA) (AMZN)	`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`
7.5High	3.1	CVEProject cvelistV5 (CNA) (AMZN)	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`

Affected products

Vendor	Product	Versions	Source
AWS	aws-smithy-http-server	v ≤ 0.66.4	CVEProject cvelistV5 (CNA)

References and advisories

https://crates.io/crates/aws-smithy-http-server/0.66.5 release-notespatch
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

Kolun on Telegram @kolunsec Exploited CVEs, key news and a daily digest Alerts for this product's next CVEsFollow the product to get new vulnerabilities on Telegram.

Details

Published: 2026-07-23
Last updated: 2026-08-12
State: Published
Assigner (CNA): AMZN

Exploit prediction (EPSS)

0.75%

Probability of exploitation in 30 days

55.2%

Percentile (among all CVEs)

SSVC assessment (CISA)

Automatable: Yes
Exploitation: None
Technical impact: Partial

Weaknesses (CWE)

CWE-770
Allocation of resources without limits or throttling