# blaze: Chunked-body trailer fields promoted into Request.headers in blaze-server (front-end header-sanitization bypass) Advisory record · `GHSA-46q4-43ph-c6fr` - **Identifiers:** `GHSA-46q4-43ph-c6fr` · `CVE-2026-73495` - **State:** Confirmed - **Severity:** CVSS 7.4 High - **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:** 24 Jul 2026 - **Updated:** 12 Aug 2026 - **Reviewed by a person:** No Published by the GitHub Advisory Database at 24 Jul 2026, 22:26 UTC. agentprime has not analysed this yet, so whether it affects any app is not known. ## Affected packages - `org.http4s:blaze-http_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:blaze-http_2.12` (Maven): affected `<0.23.18`; fixed in `0.23.18` - `org.http4s:blaze-http_3` (Maven): affected `<0.23.18 || >=1.0.0-M1, <1.0.0-M42`; fixed in `0.23.18`, `1.0.0-M42` ## Machine-written summary Summary written by Claude Haiku from the source advisory. Not reviewed by a person. > Blaze-http (Maven org.http4s:blaze-http_2.13, \_2.12 and \_3) is affected in versions before 0.23.18 and from 1.0.0-M1 up to 1.0.0-M42, where blaze-server can copy HTTP/1.1 chunked-body trailer fields into request headers. An unauthenticated remote client can use this to add arbitrary headers, such as X-Forwarded-For or internal-auth headers, that a fronting proxy had removed, which can bypass header-based trust decisions in the application. Upgrade to 0.23.18 or 1.0.0-M42. If upgrading is not possible, deploy behind a proxy that strips trailer fields or rejects requests that use them. 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 - 7.4 High, CVSS 3.1: `CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N`, from CNA (GitHub_M) - **CISA KEV:** Not listed. - **EPSS:** 0.0048, the 41st percentile, on 5 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-46q4-43ph-c6fr) ## Sources - [GitHub Advisory Database: GHSA-46q4-43ph-c6fr](https://github.com/advisories/GHSA-46q4-43ph-c6fr) - [OSV: GHSA-46q4-43ph-c6fr](https://osv.dev/vulnerability/GHSA-46q4-43ph-c6fr) - - - - - 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: .