praktor: Path traversal in Telegram file uploads allows writing outside the agent workspace uploads/ directory (stored instruction injection)

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

8.2 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N

EPSS

• CVE-2026-62331: 0.78% estimated exploitation activity in the next 30 days; percentile 55.90 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact A remote Telegram user can write files to arbitrary paths inside an agent's persistent workspace volume (`praktor-wk- `, mounted at `/workspace/agent`), escaping the documented `uploads/` directory. The attacker controls the Telegram document filename, which was concatenated into the destination path without sanitization (`internal/telegram/bot.go`, at both upload sites) and resolved with `path.Join`, which collapses `../` sequences. A filename like `../../../CLAUDE.md` resolved to the root of the agent workspace volume, outside `uploads/`. Because the agent workspace is the persistent working directory the Claude agent reads from and operates on across runs, writing outside `uploads/` lets an attacker plant or overwrite files the agent later consumes — e.g. `CLAUDE.md`, agent instruction/skill/hook files, or other config under `/workspace/agent`. This turns a file upload into a stored injection into the agent's instruction/execution surface (CWE-22 path traversal…

Published by the source

3 Nov 2026, 17:27 UTC

Last modified by the source

3 Nov 2026, 17:45 UTC

Source last checked

4 Nov 2026, 06:30 UTC

1. Revision 2 · amended · 4 Nov 2026

   Amended from osv record GHSA-48v2-6jcm-fc99

2. Revision 1 · created · 3 Nov 2026

   Published from ghsa record GHSA-48v2-6jcm-fc99

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# Patch Next advisory brief: CVE-2026-62331

Advisory: praktor: Path traversal in Telegram file uploads allows writing outside the agent workspace uploads/ directory (stored instruction injection)
IDs: CVE-2026-62331, GHSA-48v2-6jcm-fc99
Record: https://patchnext.com/advisories/cve-2026-62331 (revision 2, source checked 4 Nov 2026, 06:30 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.2)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/mtzanidakis/praktor 0.9.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/mtzanidakis/praktor: affected < 0.9.1; fixed in 0.9.1

## Suggested inspection (read-only)
- Go github.com/mtzanidakis/praktor: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/mtzanidakis/praktor.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-48v2-6jcm-fc99 (GitHub-reviewed advisory GHSA-48v2-6jcm-fc99 lists affected ranges: Go github.com/mtzanidakis/praktor >=0 <=0.9.0)
- Verified: https://osv.dev/vulnerability/GHSA-48v2-6jcm-fc99 (OSV record GHSA-48v2-6jcm-fc99 lists affected ranges: Go github.com/mtzanidakis/praktor >=0 <0.9.1 (fixed))

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