# CVE-2025-10148: predictable WebSocket mask

> A predictable WebSocket mask in curl allows malicious servers to poison proxy caches, serving modified content to users.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 12 Sep 2025
- **Updated:** 15 Sep 2026
- **Also known as:** ALPINE-CVE-2025-10148, AZL-67082, AZL-67272, AZL-67290, BELL-CVE-2025-10148, CLEANSTART-2026-US71210, CURL-CVE-2025-10148, DEBIAN-CVE-2025-10148, ECHO-0bd8-fe65-a70f, GHSA-cxvq-c3r3-8gwq, JLSEC-2026-423, MINI-9wj9-v876-v8x9, ROOT-OS-DEBIAN-12-CVE-2025-10148, UBUNTU-CVE-2025-10148

## What is CVE-2025-10148?

CVE-2025-10148 is a medium-severity vulnerability in Haxx Curl, published on 12 Sep 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

curl's WebSocket code did not update the 32-bit mask pattern for each new
outgoing frame as the specification says. Instead it used a fixed mask that
persisted and was used throughout the entire connection.

A predictable mask pattern allows for a malicious server to induce traffic
between the two communicating parties that could be interpreted by an involved
proxy (configured or transparent) as genuine, real, HTTP traffic with content
and thereby poison its cache. That cached poisoned content could then be
served to all users of that proxy.

Weakness: CWE-340 (Generation of Predictable Numbers or Identifiers)

## Which versions are affected by CVE-2025-10148?

It affects 1 product.


Products: Haxx Curl.

## How do I fix CVE-2025-10148?

Upgrade to a fixed version.

## Is CVE-2025-10148 being exploited?

There is no known exploitation of CVE-2025-10148 in the wild and no public exploit code.

## Other vulnerabilities in Haxx Curl

- [CVE-2026-19931](https://insights.sbomify.com/CVE-2026-19931/): Negotiate ambient user conn reuse (critical 9.8)
- [CVE-2026-10536](https://insights.sbomify.com/CVE-2026-10536/): HTTP/2 stream-dependency tree UAF (critical 9.8)
- [CVE-2026-11856](https://insights.sbomify.com/CVE-2026-11856/): cross-origin Digest auth state leak (critical 9.8)
- [CVE-2026-8925](https://insights.sbomify.com/CVE-2026-8925/): SASL double-free (critical 9.8)
- [CVE-2026-9079](https://insights.sbomify.com/CVE-2026-9079/): stale proxy password leak (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-10148 and fix it if it is affected.

What it is: CVE-2025-10148 is a medium-severity vulnerability in Haxx Curl, published on 12 Sep 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-10148 in the wild and no public exploit code.

Affected product: Haxx Curl. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2025-10148/ (Markdown: https://insights.sbomify.com/CVE-2025-10148/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-10148
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-10148
- OSV: https://osv.dev/vulnerability/CVE-2025-10148

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-10148/
Summaries are generated and may contain mistakes; the official description above is the record.