# CVE-2026-101899: Axios: CIDR-form NO_PROXY entries are ignored, causing proxy exclusion bypass for internal IP ranges

> Axios ignores CIDR-form NO_PROXY entries, causing internal requests to bypass intended exclusions and traverse configured proxies, exposing data to interception.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:N/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:** 13 Oct 2026
- **Updated:** 14 Oct 2026
- **Also known as:** CLEANSTART-2026-FC45371, CLEANSTART-2026-HE03730, CLEANSTART-2026-SK85007, DEBIAN-CVE-2026-101899, ECHO-322b-b4b4-8549, GHSA-44g4-m2mj-wpvx, MINI-33rx-8cx5-fvpf, MINI-3v36-h9jf-crvr, MINI-4r7g-h35f-34j8, MINI-57rw-xc7m-f2w3, MINI-739w-67f7-pgm4, MINI-g7mh-6qv9-hg66, MINI-hhcw-q6r5-pq9f, MINI-jwqw-rh4p-5h2q, MINI-rrr5-4j9w-56c8, MINI-vmwv-3rmm-2f52, MINI-xv7c-wjgr-c6mr, UBUNTU-CVE-2026-101899

## What is CVE-2026-101899?

CVE-2026-101899 is a medium-severity vulnerability in axios, published on 13 Oct 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 1.15.0 until 1.20.0, Axios shouldBypassProxy treats the NO_PROXY CIDR form as a textual hostname suffix instead of evaluating the network range. A request targets an address covered by a CIDR entry in NO_PROXY while a proxy is configured. The CIDR bypass rule is not matched, so the request is sent through the configured proxy. For plaintext HTTP, the proxy can observe and modify URLs, headers, and bodies; for HTTPS, it can observe connection metadata and CONNECT requests. This issue is fixed in version 1.20.0.

Weakness: CWE-693 (Protection Mechanism Failure)

## Which versions are affected by CVE-2026-101899?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `axios` | npm | From 1.15.0 | 1.20.0 |
| `axios` | npm | From 1.15.0 | 1.20.0 |

## How do I fix CVE-2026-101899?

Upgrade axios to 1.20.0 or later.

## Is CVE-2026-101899 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-101899 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-101899 and fix it if it is affected.

What it is: CVE-2026-101899 is a medium-severity vulnerability in axios, published on 13 Oct 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-2026-101899 exists.

Affected packages and fixed versions:
- axios (npm): affected from 1.15.0; fixed in 1.20.0
- axios (npm): affected from 1.15.0; 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-2026-101899/ (Markdown: https://insights.sbomify.com/CVE-2026-101899/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-101899
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-101899
- OSV: https://osv.dev/vulnerability/CVE-2026-101899

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-101899/
Summaries are generated and may contain mistakes; the official description above is the record.