# blaze: Unbounded WebSocket message aggregation in http4s-blaze-server Advisory record · `GHSA-7ppr-r889-mcf2` - **Identifiers:** `GHSA-7ppr-r889-mcf2` · `CVE-2026-73493` - **State:** Confirmed - **Severity:** CVSS 7.5 High - **Critical:** No - **Weakness (CWE):** [CWE-770](https://cwe.mitre.org/data/definitions/770.html) - **Tags:** [Denial of service](https://agentprime.io/advisories/tag/dos.md) - **Published:** 24 Jul 2026 - **Updated:** 12 Aug 2026 - **Reviewed by a person:** No Published by the GitHub Advisory Database at 24 Jul 2026, 22:28 UTC. agentprime has not analysed this yet, so whether it affects any app is not known. ## Affected packages - `org.http4s:http4s-blaze-server_2.13` (Maven): affected `<0.23.18 || >=1.0.0-M1, <1.0.0-M42`; fixed in `0.23.18`, `1.0.0-M42` - `org.http4s:http4s-blaze-server_2.12` (Maven): affected `<0.23.18`; fixed in `0.23.18` - `org.http4s:http4s-blaze-server_3` (Maven): affected `>=1.0.0-M1, <1.0.0-M42`; fixed in `1.0.0-M42` ## Machine-written summary Summary written by Claude Haiku from the source advisory. Not reviewed by a person. > Versions of http4s-blaze-server before 0.23.18, and from 1.0.0-M1 up to but not including 1.0.0-M42, are affected. A client that completes a WebSocket handshake can send a fragmented message that is never terminated, forcing the server to buffer fragments without limit until the JVM runs out of memory and crashes. Upgrade to 0.23.18 or 1.0.0-M42. No configuration option bounds the buffering, so the only listed workaround is to limit WebSocket traffic at a fronting layer or disable WebSocket routes. 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 - 7.5 High, CVSS 3.1: `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`, from CNA (GitHub_M) - **CISA KEV:** Not listed. - **EPSS:** 0.0063, the 50th percentile, on 7 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-7ppr-r889-mcf2) ## Sources - [GitHub Advisory Database: GHSA-7ppr-r889-mcf2](https://github.com/advisories/GHSA-7ppr-r889-mcf2) - [OSV: GHSA-7ppr-r889-mcf2](https://osv.dev/vulnerability/GHSA-7ppr-r889-mcf2) - - - - - - - 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 (), 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: - In a browser: reads your lockfile in the browser, never uploading it. - Whether it touches your code, with file and line: the Claude Code plugin, - As JSON: , or `POST https://api.agentprime.io/v1/match` with your packages () --- The web page: . Everything for agents: .