# Poly1305 panics or computes a wrong tag on attacker-chosen messages of 64 bytes or more Advisory record · `GHSA-xr22-8pqp-gwfh` - **Identifiers:** `GHSA-xr22-8pqp-gwfh` · `RUSTSEC-2026-0337` - **State:** Confirmed - **Severity:** CVSS 7.5 High - **Critical:** No - **Published:** 9 Oct 2026 - **Updated:** 12 Oct 2026 - **Reviewed by a person:** No Published by the GitHub Advisory Database at 9 Oct 2026, 12:00 UTC. agentprime has not analysed this yet, so whether it affects any app is not known. ## Affected packages - `ic-cipher` (crates.io): affected `>=0.2.5, <0.2.20`; fixed in `0.2.20` ## Machine-written summary Summary written by Claude Haiku from the source advisory. Not reviewed by a person. > Poly1305 and ChaCha20-Poly1305 in ic-cipher versions 0.2.5 through 0.2.19 can panic or compute a wrong authentication tag on messages of 64 bytes or more. An attacker who can deliver a ChaCha20-Poly1305 ciphertext for opening can trigger the panic, which ends the process under panic = "abort" in builds with overflow checks on, and no key is needed. Upgrade ic-cipher to 0.2.20. 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 - 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 OSV - **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-2026-0337) ## Sources - [GitHub Advisory Database: GHSA-xr22-8pqp-gwfh](https://github.com/advisories/GHSA-xr22-8pqp-gwfh) - [OSV: GHSA-xr22-8pqp-gwfh](https://osv.dev/vulnerability/GHSA-xr22-8pqp-gwfh) - - - 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: .