# HTTP Request Smuggling in akka-http-core

Advisory record · `GHSA-2w7w-2j92-44hx`

- **Identifiers:** `GHSA-2w7w-2j92-44hx` · `CVE-2021-23339` · `SNYK-JAVA-COMTYPESAFEAKKA-1075043`
- **State:** Confirmed
- **Severity:** CVSS 5.0 Medium
- **Critical:** No
- **Weakness (CWE):** [CWE-444](https://cwe.mitre.org/data/definitions/444.html)
- **Tags:** [HTTP request smuggling](https://agentprime.io/advisories/tag/request-smuggling.md)
- **Published:** 10 May 2021
- **Updated:** 8 Jul 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 10 May 2021, 15:17 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `com.typesafe.akka:akka-http-core` (Maven): affected `>=10.2.0, <10.2.4 || <10.1.14`; fixed in `10.2.4`, `10.1.14`

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> Akka HTTP core (com.typesafe.akka:akka-http-core) versions 10.2.0 before 10.2.4 and before 10.1.14 are vulnerable to HTTP request smuggling. A server accepts a malformed message and passes it to the application, which may forward it unchanged to a second server that reads it as two messages, so the second request bypasses inspection by the proxy. Upgrade to version 10.2.4 or 10.1.14.

Written 2 Nov 2026.

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 5.0 Medium, CVSS 3.1: `CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:L`, from CNA (snyk)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0071, the 53rd percentile, on 8 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 14:19 UTC: First seen by agentprime
- 31 Oct 2026, 14:19 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-2w7w-2j92-44hx)

## Sources

- [GitHub Advisory Database: GHSA-2w7w-2j92-44hx](https://github.com/advisories/GHSA-2w7w-2j92-44hx)
- [OSV: GHSA-2w7w-2j92-44hx](https://osv.dev/vulnerability/GHSA-2w7w-2j92-44hx)
- <https://nvd.nist.gov/vuln/detail/CVE-2021-23339>
- <https://github.com/akka/akka-http/pull/3754%23issuecomment-779265201>
- <https://github.com/akka/akka-http/commit/e3a4935151c91cee28e65e6b894dd50839ef9d34>
- <https://doc.akka.io/docs/akka-http/10.1/security/2021-02-24-incorrect-handling-of-Transfer-Encoding-header.html>
- <https://snyk.io/vuln/SNYK-JAVA-COMTYPESAFEAKKA-1075043>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-2w7w-2j92-44hx>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-2w7w-2j92-44hx/>. Everything for agents: <https://agentprime.io/llms.txt>.