Axios: Null Byte Injection via Reverse-Encoding in AxiosURLSearchParams

published 2026-04-24 6mo ago modified 2026-09-10 last mo. also EUVD-2026-25590 , GHSA-xhjh-pmcv-23jw

cvss: 3.7; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.2%; EPSS 0.2% chance of exploitation in 30 days, percentile 12%
public exploits: 0; none known

Axios is a promise based HTTP client for the browser and Node.js. Prior to 1.15.1 and 0.31.1, the encode() function in lib/helpers/AxiosURLSearchParams.js contains a character mapping (charMap) at line 21 that reverses the safe percent-encoding of null bytes. After encodeURIComponent('\x00') correctly produces the safe sequence %00, the charMap entry '%00': '\x00' converts it back to a raw null byte. Primary impact is limited because the standard axios request flow is not affected. This vulnerability is fixed in 1.15.1 and 0.31.1.

Patch / fix

fixed in 2 distros 1

npm axios 0.31.1, 1.15.1
axios axios 0.31.1, 1.15.1

node-axios Debian 14 1.15.2-1

debian advisories DEBIAN-CVE-2026-42040

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Vendor advisories

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red hat product security vex CVE-2026-42040 updated 2026-11-07 cvss 3.7

axios: Axios: Incorrect null byte handling can lead to data integrity issues

Red Hat Cryostat 4 axios, cryostat-openshift-console-plugin-npm Red Hat Gatekeeper 3 gatekeeper/gatekeeper-rhel9 Red Hat Migration Toolkit for Applications 8 mta/mta-ui-rhel8, mta/mta-ui-rhel9 Red Hat Migration Toolkit for Containers rhmtc/openshift-migration-ui-rhel8 Red Hat Multicluster Engine for Kubernetes multicluster-engine/console-mce-rhel9 Red Hat Network Observability Operator network-observability/network-observability-console-plugin-rhel9, network-observability/network-observability-console-plugin-pf4-rhel9, network-observability/network-observability-console-plugin-pf5-rhel9, network-observability/network-observability-console-plugin-compat-rhel9

+34 more productsfewer

Red Hat OpenShift Pipelines openshift-pipelines/pipelines-hub-ui-rhel8, openshift-pipelines/pipelines-hub-ui-rhel9 Red Hat OpenShift Service Mesh 2 openshift-service-mesh/kiali-rhel8, openshift-service-mesh/kiali-ossmc-rhel8 Red Hat OpenShift Service Mesh 3 openshift-service-mesh/kiali-rhel9, openshift-service-mesh/kiali-ossmc-rhel9, openshift-service-mesh/kiali-rhel9-operator, openshift-service-mesh/kiali-operator-bundle Red Hat 3scale API Management Platform 2 3scale-amp21/system, 3scale-amp22/system, 3scale-amp2/system-rhel7, 3scale-amp2/system-rhel8, 3scale-amp2/system-rhel9 Red Hat Advanced Cluster Management for Kubernetes 2 rhacm2/console-rhel9 Red Hat Advanced Cluster Security 4 advanced-cluster-security/rhacs-main-rhel8, advanced-cluster-security/rhacs-main-rhel9 Red Hat AMQ Broker 7 axios Red Hat Ansible Automation Platform 2 automation-hub, python-galaxy-ng, automation-gateway, python3x-galaxy-ng, python3.11-galaxy-ng, python3.12-galaxy-ng, +5 more Red Hat build of Apache Camel - HawtIO 4 axios Red Hat build of Apache Camel for Spring Boot 4 axios Red Hat build of Apicurio Registry 2 axios Red Hat build of Apicurio Registry 3 apicurio/apicurio-registry-ui-rhel8, apicurio/apicurio-registry-ui-rhel9 Red Hat Build of Podman Desktop - Tech Preview rhdesktop/rh-podman-desktop-ext-openshift-local-rhel10 Red Hat Connectivity Link 1 rhcl-1/rhcl-console-plugin-rhel9 Red Hat Data Grid 8 axios Red Hat Developer Hub 1 rhdh/rhdh-hub-rhel9 Red Hat Discovery 2 discovery/discovery-ui-rhel9 Red Hat Enterprise Linux 8 grafana, grafana-pcp, grafana-loki, grafana-mssql, grafana-mysql, grafana-selinux, +9 more Red Hat Enterprise Linux 9 grafana, grafana-selinux Red Hat Enterprise Linux AI (RHEL AI) 3 rhelai3/bootc-cuda-rhel9, rhelai3/bootc-rocm-rhel9, rhelai3/bootc-gaudi-rhel9, rhelai3/disk-image-cuda-rhel9 Red Hat Fuse 7 axios Red Hat OpenShift AI (RHOAI) rhoai/odh-mlflow-rhel9, rhoai/odh-dashboard-rhel9, rhoai/odh-mod-arch-maas-rhel9, rhoai/odh-mod-arch-automl-rhel9, rhoai/odh-mod-arch-gen-ai-rhel9, rhoai/odh-mod-arch-mlflow-rhel9, +3 more Red Hat OpenShift Container Platform 4 openshift3/ose-console, openshift4/ose-console, openshift4/ose-console-rhel9, openshift4/ose-monitoring-plugin-rhel9, openshift4/ose-agent-installer-ui-rhel9 Red Hat OpenShift Container Platform 5 openshift5/ose-monitoring-plugin-rhel9, openshift5/ose-agent-installer-ui-rhel9 Red Hat OpenShift Dev Spaces devspaces/code-rhel9, devspaces/dashboard-rhel9 Red Hat OpenShift Virtualization 4 container-native-virtualization/kubevirt-console-plugin, container-native-virtualization/kubevirt-console-plugin-rhel9 Red Hat Process Automation 7 axios Red Hat Quay 3 quay/quay-rhel8, quay/quay-rhel9 Red Hat Satellite 6 satellite/iop-advisor-frontend-rhel9, satellite/iop-vulnerability-frontend-rhel9, satellite/iop-host-inventory-frontend-rhel9 Red Hat Trusted Artifact Signer rhtas/rhtas-console-ui-rhel9 Red Hat Trusted Profile Analyzer rhtpa/rhtpa-trustification-service-rhel9 Red Hat Self-service automation portal 2 ansible-automation-platform/automation-portal, ansible-automation-platform/bootc-automation-portal-rhel9 Red Hat streams for Apache Kafka 2 axios Red Hat streams for Apache Kafka 3 axios

affected: workaround, no fix available “Fix deferred”

1 more fixed, 1 more not affected in the full advisory

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: Proof of concept is public
Automatable: no
Technical impact: partial
Assessed: 6mo ago (2026-04-27)

Exploit prediction

0.22% chance of exploitation in the next 30 days, higher than 12% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

github.com https://github.com/axios/axios/security/advisories/GHSA-xhjh-pmcv-23jw referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	3.1	3.7	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
GitHub	3.1	3.7	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

Affected packages

ecosystem	package	affected	fixed in
npm	axios	>=1.0.0, <1.15.1 <0.31.1	1.15.1 0.31.1

Affected products

axios axios

Classification

Weakness

CWE-116 Improper Encoding or Escaping of Output
CWE-626 Null Byte Interaction Error (Poison Null Byte)

References

github.com /axios/axios/security/advisories/GHSA-xhjh-pmcv-23jw
exploit, web, mitigation, vendor-advisory
nvd.nist.gov /vuln/detail/CVE-2026-42040
advisory
github.com /axios/axios
package

Sources

Fencer Intel 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.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.