CVE-2026-18140

Exploitation

Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.

SSVC decision

• ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
• AutomatableyesAn attacker can reliably automate reconnaissance through exploitation, so this scales.
• Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.

CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.

EPSS probability

0.43% probability of exploitation activity in the next 30 days.

EPSS percentile

Ranks above 35.6% of scored records. A rank, not a probability.

NVD base score

8.7 (CVSS v4.0), scored by the NVD independently of the CNA.

NVD CVSS vector

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

NVD analysis status

Analyzed. NVD last modified this record on 2026-08-10.

Red Hat severity

Important. Red Hat's rating for its own products, not a CVSS rating.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

Published

2026-07-30 18:34Z1 MO AGO

Last updated

2026-07-30 19:12Z1 MO AGO

Reserved

2026-07-28

Assigning CNA

AMZN

Record state

PUBLISHED

Severity

High (CVSS 8.7)

CNA CVSS vector

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

Weaknesses

• CWE-674Uncontrolled RecursionClass
• CWE-776Improper Restriction of Recursive Entity References in DTDs ('XML Entity Expansion')Base

Data version

5.2

Document digest

23fb83935440368b117d96b660c4349091d6f36d4ec0bff9d8ec4e2d2aa22384

• crates.iohttps://crates.io/crates/aws-smithy-json/0.62.7patch
• aws.amazon.comhttps://aws.amazon.com/security/security-bulletins/2026-067-aws/vendor-advisory
• github.comhttps://github.com/smithy-lang/smithy-rs/security/advisories/GHSA-8ffr-xgwf-xj56third-party-advisory