# Ability to expose data in Sylius by using an unintended serialisation group Advisory record · `GHSA-8vp7-j5cj-vvm2` - **Identifiers:** `GHSA-8vp7-j5cj-vvm2` · `CVE-2020-5218` · `CVE-2020-5220` · `GHSA-prg5-hg25-8grq` · `PKSA-3b3k-ptfz-1wwy` · `PKSA-bpp9-7wqw-wr8k` · `PKSA-sjsn-7352-ttw3` - **State:** Confirmed - **Severity:** CVSS 4.4 Medium - **Critical:** No - **Weakness (CWE):** [CWE-200](https://cwe.mitre.org/data/definitions/200.html) · [CWE-444](https://cwe.mitre.org/data/definitions/444.html) - **Tags:** [Information disclosure](https://agentprime.io/advisories/tag/info-disclosure.md) · [HTTP request smuggling](https://agentprime.io/advisories/tag/request-smuggling.md) - **Published:** 31 Jan 2020 - **Updated:** 8 Jul 2026 - **Reviewed by a person:** No Published by the GitHub Advisory Database at 31 Jan 2020, 18:00 UTC. agentprime has not analysed this yet, so whether it affects any app is not known. ## Affected packages - `sylius/resource-bundle` (Packagist): affected `>=1.4.0, <1.4.6 || >=1.5.0, <1.5.1 || >=1.6.0, <1.6.3 || >=1.0.0, <1.3.13`; fixed in `1.4.6`, `1.5.1`, `1.6.3`, `1.3.13` - `sylius/sylius` (Packagist): affected `<1.3.12 || >=1.4.0, <1.4.4`; fixed in `1.3.12`, `1.4.4` ## Machine-written summary Summary written by Claude Haiku from the source advisory. Not reviewed by a person. > Sylius resource-bundle versions before 1.3.13, from 1.4.0 before 1.4.6, 1.5.0 before 1.5.1, and 1.6.0 before 1.6.3 accept arbitrary serialisation groups passed through an HTTP header. An attacker who can reach an API built on the bundle's controller can use a more permissive group, such as one from the Admin API on the Shop API, and so expose data. Upgrade sylius/resource-bundle to 1.3.13, 1.4.6, 1.5.1, or 1.6.3. Users with custom groups sent via the header must add them to allowed_serialization_groups, as the fix breaks backward compatibility. Written 3 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 - 4.4 Medium, CVSS 3.1: `CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:N`, from CNA (GitHub_M) - **CISA KEV:** Not listed. - **EPSS:** 0.0074, the 54th percentile, on 9 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days. ## Timeline - 31 Oct 2026, 14:25 UTC: First seen by agentprime - 31 Oct 2026, 14:25 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-8vp7-j5cj-vvm2) ## Sources - [GitHub Advisory Database: GHSA-8vp7-j5cj-vvm2](https://github.com/advisories/GHSA-8vp7-j5cj-vvm2) - [OSV: GHSA-8vp7-j5cj-vvm2](https://osv.dev/vulnerability/GHSA-8vp7-j5cj-vvm2) - - - - 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: .