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← Actionable
Medium, CVSS 5.3amended

Axios' HTTP adapter-streamed uploads bypass maxBodyLength when maxRedirects: 0

CVE-2026-42034GHSA-5c9x-8gcm-mpgx

What to do

Vendor fix available. Upgrade each affected package to the fixed version on its release line (axios 1.15.1, 0.31.1), redeploy, then verify what is actually installed.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

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Affected packages

  • npm axios

    Affected
    >= 1.0.0, < 1.15.1<= 0.31.0
    Fixed in
    0.31.1, 1.15.1

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS
5.3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
EPSS
  • CVE-2026-42034: 0.33% estimated exploitation activity in the next 30 days; percentile 25.88 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description

As published by the source; long descriptions are shortened.

Summary For stream request bodies, maxBodyLength is bypassed when maxRedirects is set to 0 (native http/https transport path). Oversized streamed uploads are sent fully even when the caller sets strict body limits. Details Relevant flow in lib/adapters/http.js: - 556-564: maxBodyLength check applies only to buffered/non-stream data. - 681-682: maxRedirects === 0 selects native http/https transport. - 694-699: options.maxBodyLength is set, but native transport does not enforce it. - 925-945: stream is piped directly to socket (data.pipe(req)) with no Axios byte counting. This creates a path-specific bypass for streamed uploads.

PoC Environment: - Axios main at commit f7a4ee2 - Node v24.2.0 Steps: 1. Start an HTTP server that counts uploaded bytes and returns {received}. 2. Send a 2 MiB Readable stream with: - adapter: 'http' - maxBodyLength: 1024 - maxRedirects: 0 Observed: - Request succeeds; server reports received: 2097152. Control checks: - Same stream with default/nonzero…

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 2 · amended ·

    Amended from ghsa record GHSA-5c9x-8gcm-mpgx

  2. Revision 1 · created ·

    Published from osv record GHSA-5c9x-8gcm-mpgx

Agent brief

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# Patch Next advisory brief: CVE-2026-42034

Advisory: Axios' HTTP adapter-streamed uploads bypass maxBodyLength when maxRedirects: 0
IDs: CVE-2026-42034, GHSA-5c9x-8gcm-mpgx
Record: https://patchnext.com/advisories/cve-2026-42034 (revision 2, source checked 26 Oct 2026, 12:51 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: axios 1.15.1, 0.31.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm axios: affected >= 1.0.0, < 1.15.1; <= 0.31.0; fixed in 0.31.1, 1.15.1

## Suggested inspection (read-only)
- `npm ls axios --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on axios.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-5c9x-8gcm-mpgx (OSV record GHSA-5c9x-8gcm-mpgx lists affected ranges: npm axios >=1.0.0 =0 <0.31.1 (fixed))
- Verified: https://github.com/advisories/GHSA-5c9x-8gcm-mpgx (GitHub-reviewed advisory GHSA-5c9x-8gcm-mpgx lists affected ranges: npm axios >=1.0.0 =0 <=0.31.0)

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