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Fencer Vulns
high 7.5

CVE-2026-18140 json

Uncontrolled recursion in the aws-smithy-json unknown-key skip path allows unauthenticated remote denial of service in smithy-rs generated servers

published 2026-07-30 3 mo ago modified 2026-10-23 16 d ago also GHSA-8ffr-xgwf-xj56 , EUVD-2026-51271

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.8%
EPSS 0.8% chance of exploitation in 30 days, percentile 56%
public exploits
0
none known

Summary

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.

Patch / fix

  • crates.io aws-smithy-json 0.62.7
  • amazon aws-smithy-json 0.62.7
  • goose RHEL 10.2 1.38.0-1.el10_2
  • goose RHEL 9 1.38.0-1.el9_8

red hat advisories RHSA-2026:67593RHSA-2026:67595

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-18140 updated cvss 7.5

aws-smithy-json: aws-smithy-json: Denial of Service via uncontrolled recursion with deeply nested JSON

  • Red Hat Trusted Profile Analyzer rhtpa/rhtpa-trustification-service-rhel9
    affected: workaround, no fix planned “Will not fix”
  • Red Hat Logging Subsystem for Red Hat OpenShift 6.0 openshift-logging/vector-rhel9 1791777198
    fixed: vendor fix RHSA-2026:83013
  • Red Hat Logging Subsystem for Red Hat OpenShift 6.2 openshift-logging/vector-rhel9 1789050538
    fixed: vendor fix RHSA-2026:68349
  • Red Hat Logging Subsystem for Red Hat OpenShift 6.5 openshift-logging/vector-rhel9 1789659541
    fixed: vendor fix RHSA-2026:70870
  • Red Hat Logging Subsystem for Red Hat OpenShift 6.6 openshift-logging/vector-rhel9 1788439747
    fixed: vendor fix RHSA-2026:66521
  • Red Hat Enterprise Linux Extensions Channel (v. 9) goose 1.38.0-1.el9_8
    fixed: vendor fix RHSA-2026:67595
  • Red Hat Enterprise Linux Extensions Channel (v. 10) goose 1.38.0-1.el10_2
    fixed: vendor fix RHSA-2026:67593
  • Red Hat Trusted Artifact Signer 1.4 rhtas/tuffer-rhel9 1791809629, rhtas/tuftool-rhel9 1791809629
    fixed: vendor fix RHSA-2026:83603
show 1 more
  • Red Hat Confidential Compute Attestation build-of-trustee/trustee-rhel9 Red Hat Logging Subsystem for Red Hat OpenShift 6.0 openshift-logging/eventrouter-rhel9 1791500947, openshift-logging/logging-loki-rhel9 1791500729, openshift-logging/loki-rhel9-operator 1791499216, openshift-logging/opa-openshift-rhel9 1791500883, openshift-logging/loki-operator-bundle 1791504713, openshift-logging/lokistack-gateway-rhel9 1791500864, +3 more Red Hat Logging Subsystem for Red Hat OpenShift 6.2 openshift-logging/eventrouter-rhel9 1789050399, openshift-logging/logging-loki-rhel9 1789050556, openshift-logging/loki-rhel9-operator 1789050212, openshift-logging/opa-openshift-rhel9 1789050227, openshift-logging/loki-operator-bundle 1789053077, openshift-logging/lokistack-gateway-rhel9 1789050242, +3 more Red Hat Logging Subsystem for Red Hat OpenShift 6.5 openshift-logging/eventrouter-rhel9 1789659145, openshift-logging/logging-loki-rhel9 1789736915, openshift-logging/loki-rhel9-operator 1789736807, openshift-logging/opa-openshift-rhel9 1789659129, openshift-logging/loki-operator-bundle 1789737942, openshift-logging/lokistack-gateway-rhel9 1789659121, +3 more Red Hat Logging Subsystem for Red Hat OpenShift 6.6 openshift-logging/eventrouter-rhel9 1788375796, openshift-logging/logging-loki-rhel9 1788156390, openshift-logging/loki-rhel9-operator 1788154255, openshift-logging/opa-openshift-rhel9 1788153362, openshift-logging/loki-operator-bundle 1788158124, openshift-logging/lokistack-gateway-rhel9 1788153356, +3 more Red Hat Trusted Profile Analyzer rhtpa/rhtpa-rhel10
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
3 mo ago

Exploit prediction

0.78% chance of exploitation in the next 30 days, higher than 56% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA 4.0 8.7 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
CNA 4.0 8.7 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
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
crates.io aws-smithy-json
<0.62.7
0.62.7

Affected products

  • AWS aws-smithy-json

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.