# Prefix Truncation Attack against ChaCha20-Poly1305 and Encrypt-then-MAC aka Terrapin

Advisory record · `GHSA-45x7-px36-x8w8`

- **Identifiers:** `GHSA-45x7-px36-x8w8` · `CVE-2023-48795` · `GO-2023-2402` · `PYSEC-2026-1758`
- **State:** Confirmed
- **Severity:** CVSS 5.9 Medium
- **Critical:** No
- **Weakness (CWE):** [CWE-345](https://cwe.mitre.org/data/definitions/345.html) · [CWE-354](https://cwe.mitre.org/data/definitions/354.html)
- **Tags:** [CWE-345](https://agentprime.io/advisories/tag/cwe-345.md) · [CWE-354](https://agentprime.io/advisories/tag/cwe-354.md)
- **Published:** 18 Dec 2023
- **Updated:** 10 Sept 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 18 Dec 2023, 19:22 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `russh` (crates.io): affected `<0.40.2`; fixed in `0.40.2`
- `golang.org/x/crypto` (Go): affected `>=0.1.0, <0.17.0 || <0.0.0-20231218163308-9d2ee975ef9f`; fixed in `0.17.0`, `0.0.0-20231218163308-9d2ee975ef9f`
- `paramiko` (PyPI): affected `>=2.5.0, <3.4.0`; fixed in `3.4.0`

## 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

- 5.9 Medium, CVSS 3.1: `CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N`, from GitHub Advisory Database

- **CISA KEV:** Not listed.
- **EPSS:** 0.94, the 99th percentile, on 6 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 14:15 UTC: First seen by agentprime
- 31 Oct 2026, 14:15 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-45x7-px36-x8w8)

## Sources

- [GitHub Advisory Database: GHSA-45x7-px36-x8w8](https://github.com/advisories/GHSA-45x7-px36-x8w8)
- [OSV: GHSA-45x7-px36-x8w8](https://osv.dev/vulnerability/GHSA-45x7-px36-x8w8)
- <https://github.com/warp-tech/russh/security/advisories/GHSA-45x7-px36-x8w8>
- <https://nvd.nist.gov/vuln/detail/CVE-2023-48795>
- <https://github.com/ssh-mitm/ssh-mitm/issues/165>
- <https://github.com/hierynomus/sshj/issues/916>
- <https://github.com/janmojzis/tinyssh/issues/81>
- <https://github.com/cyd01/KiTTY/issues/520>
- <https://github.com/proftpd/proftpd/issues/456>
- <https://github.com/apache/mina-sshd/issues/445>
- <https://github.com/paramiko/paramiko/issues/2337#issuecomment-1887642773>
- <https://github.com/paramiko/paramiko/issues/2337>
- <https://github.com/PowerShell/Win32-OpenSSH/issues/2189>
- <https://github.com/mwiede/jsch/issues/457>

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 (<https://api.agentprime.io/mcp>), 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: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-45x7-px36-x8w8>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-45x7-px36-x8w8/>. Everything for agents: <https://agentprime.io/llms.txt>.