# CVE-2026-101904: Axios: Header Injection via Inherited headers After Minimal Interceptor

> Attackers can inject malicious headers into HTTP requests via prototype pollution, potentially bypassing security controls or modifying request data.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:H/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 28 Sep 2026
- **Updated:** 28 Sep 2026
- **Also known as:** AZL-105257, CLEANSTART-2026-LD08351, CLEANSTART-2026-OV09426, CLEANSTART-2026-XI51543, DEBIAN-CVE-2026-101904, ECHO-1fea-28a8-5aef, GHSA-j8rh-479h-cp32, MINI-38gp-vm3g-5jm3, MINI-438m-x8p5-8prv, MINI-45xw-mx4m-3mvq, MINI-5r6j-r7jf-79hx, MINI-6h4x-25rh-4j52, MINI-77rv-rxvj-m688, MINI-7cf4-mmqj-vr34, MINI-7jh6-4mcv-jx7f, MINI-8v23-c9fg-3vx2, MINI-fvrg-jwc9-9f37, MINI-h395-6mfv-whhp, MINI-j7qf-r7xq-vq3j, MINI-jcfc-w74x-2x8r, MINI-r3w9-f695-hm2v, MINI-rxcc-982w-r93h, MINI-vpx5-w7ff-fqp5, MINI-xp5q-xm26-2gqm, MINI-xx9j-v4jp-p5j4, UBUNTU-CVE-2026-101904

## What is CVE-2026-101904?

CVE-2026-101904 is a medium-severity vulnerability in axios, published on 28 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Axios is a promise-based HTTP client for the browser and Node.js. From 1.0.0 until 1.20.0, the dispatchRequest function normalizes inherited Object.prototype.headers from a replacement request configuration. A separate same-process prototype-pollution flaw sets Object.prototype.headers, and trusted request interceptors return a new ordinary configuration without an own headers property. After the interceptor chain, dispatchRequest resolves the inherited headers during normalization. Downstream request processing can observe attacker-controlled headers, including authorization-related values. This issue is fixed in version 1.20.0.

Weakness: CWE-74 (Improper Neutralization of Special Elements in Output Used by a Downstream Component), CWE-1321 (Improperly Controlled Modification of Object Prototype Attributes)

## Which versions are affected by CVE-2026-101904?

2 open source packages ship an affected version, including axios.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `axios` | npm | From 1.0.0 | 1.20.0 |
| `axios` | npm | From 1.0.0 | 1.20.0 |

## How do I fix CVE-2026-101904?

Upgrade axios to 1.20.0 or later.

## Is CVE-2026-101904 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-101904 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-101904 and fix it if it is affected.

What it is: CVE-2026-101904 is a medium-severity vulnerability in axios, published on 28 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-101904 exists.

Affected packages and fixed versions:
- axios (npm): affected from 1.0.0; fixed in 1.20.0
- axios (npm): affected from 1.0.0; fixed in 1.20.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-101904/ (Markdown: https://insights.sbomify.com/CVE-2026-101904/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-101904
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-101904
- OSV: https://osv.dev/vulnerability/CVE-2026-101904

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-101904/
Summaries are generated and may contain mistakes; the official description above is the record.