# Uninitialized memory exposed when streaming decompression of a legacy frame fails Advisory record · `RUSTSEC-2026-0403` - **Identifiers:** `RUSTSEC-2026-0403` - **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 `>=4.0.0, <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 4.0.0 up to but not including 7.4.0, and 8.0.0 up to but not including 8.2.0, of the zstd-safe crate are affected. When streaming decompression of a corrupt legacy zstd frame fails, the output buffer can be extended over uninitialized memory, so up to 32 KiB of stale heap contents may be passed on to the application's output. Whether an attacker can read this depends on where the application sends its decompressed output. 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-2026-0403) ## Sources - [OSV: RUSTSEC-2026-0403](https://osv.dev/vulnerability/RUSTSEC-2026-0403) - - - - 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: .