# Use-after-free through \`init_using_cdict\` and \`init_using_ddict\` Advisory record · `RUSTSEC-2026-0399` - **Identifiers:** `RUSTSEC-2026-0399` - **State:** Confirmed - **Severity:** No CVSS score - **Critical:** No - **Published:** 16 Oct 2026 - **Updated:** 2 Nov 2026 - **Reviewed by a person:** No Published by OSV at 16 Oct 2026, 12:00 UTC. agentprime has not analysed this yet, so whether it affects any app is not known. ## Affected packages - `zstd-safe` (crates.io): affected `>=3.0.0, <7.4.0 || >=8.0.0-0, <8.2.0`; fixed in `7.4.0`, `8.2.0` ## Machine-written summary Summary written by Claude Haiku from the source advisory. Not reviewed by a person. > Versions 3.0.0 up to 7.4.0 (exclusive) and 8.0.0 up to 8.2.0 (exclusive) of zstd-safe are affected. In these versions, the init_using_cdict and init_using_ddict functions, which are experimental and deprecated, did not tie the lifetime of the context to the dictionary, so a dictionary could be dropped while the context still referenced it, causing a use-after-free. The source gives few details on the attacker's position or what they can achieve. Upgrade to zstd-safe 7.4.0 or 8.2.0. 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 No source has published a CVSS score for this record yet. - **CISA KEV:** Not listed. - **EPSS:** No score. ## Timeline - 31 Oct 2026, 14:24 UTC: First seen by agentprime - 31 Oct 2026, 14:24 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/RUSTSEC-2026-0399) ## Sources - [OSV: RUSTSEC-2026-0399](https://osv.dev/vulnerability/RUSTSEC-2026-0399) - - - - 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: .