CVE-2026-18140: Uncontrolled recursion in the unknown-key skip path of the aws-smithy-json runtime crate before 0.62.7, which the smithy-rs code generator invokes from every generated struct deser

highCVSS 7.5CVE-2026-18140

Uncontrolled recursion in the unknown-key skip path of the aws-smithy-json runtime crate before 0.62.7, which the smithy-rs code generator invokes from every generated struct deserializer, might allow remote unauthenticated users to cause a denial of service (process abort via stack exhaustion) via a single small HTTP request containing deeply nested JSON to a smithy-rs generated server. To remediate this issue, users should upgrade to aws-smithy-json 0.62.7 or later and rebuild.

Details

Source: NVD Recent CVEs (US · database · site)
Severity: high — CVSS 7.5
Published: 2026-07-30
Last updated: 2026-07-30
Exploitation: Not in CISA KEV at last sync

Original advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-18140

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-181400.44% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 36% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-18140	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

unknownCVE-2026-18140 - Uncontrolled recursion in the aws-smithy-json unknown-key skip path allows unauthenticated re…aws

Recent advisories for Uncontrolled recursion in

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

unknownCVE-2026-67313: axios versions 0.28.0 and later contain uncontrolled recursion in formDataToJSON when processi…nvd · 2026-08-01
unknownCVE-2026-67312: axios versions from 0.28.0 before 0.33.0 and from 1.0.0 before 1.18.0 contain uncontrolled rec…nvd · 2026-08-01
unknownCVE-2026-18140 - Uncontrolled recursion in the aws-smithy-json unknown-key skip path allows unauthenticated re…aws · 2026-07-31
highCVE-2026-67215: cJSON through 1.7.19 is vulnerable to uncontrolled recursion leading to stack exhaustion when …nvd · 2026-07-29
unknownCVE-2026-66920: Pivotick contains an uncontrolled-recursion vulnerability when processing caller-supplied grap…nvd · 2026-07-28
mediumGHSA-r292-9mhp-454m: node-tar: Uncontrolled recursion in mapHas/filesFilter allows uncatchable stack-overflow …ghsa · 2026-07-24