Summary
praktor: Path traversal in Telegram file uploads allows writing outside the agent workspace uploads/ directory (stored instruction injection)
Reachability
By default the bot has no user allowlist (allow_from: [] means "allow all"), so the only precondition is that a user can message the bot. No authentication or prior privilege is required.
Affected versions
Through v0.9.0 (and HEAD 3902d29).
Patched versions
v0.9.1, containing PR #228.
Workarounds
Restrict telegram.allow_from to trusted user IDs to limit who can send uploads to the bot. Upgrading to v0.9.1 is the recommended fix.
Fix (defense in depth)
internal/telegram/bot.go: applypath.Base()to the attacker-controlled filename at both upload sites, stripping directory components and...internal/container/manager.go:WriteVolumeBytesnow rejects any path that escapes/volafterpath.Join, protecting future callers.
Credit
Reported privately by tonghuaroot, who provided a detailed root-cause analysis, a deployed end-to-end proof of concept against the real container.Manager, and fix verification.
Impact
A remote Telegram user can write files to arbitrary paths inside an agent's persistent workspace volume (praktor-wk-<workspace>, 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 escalating to stored instruction injection).
Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files. Typical impact: unauthorized file read or write outside the intended directory.
CVE-2026-62331 has a CVSS score of 8.2 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.9.1); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2026-62331? CVE-2026-62331 is a high-severity path traversal vulnerability in github.com/mtzanidakis/praktor (go), affecting versions <= 0.9.0. It is fixed in 0.9.1. Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files.
- How severe is CVE-2026-62331? CVE-2026-62331 has a CVSS score of 8.2 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of github.com/mtzanidakis/praktor are affected by CVE-2026-62331? github.com/mtzanidakis/praktor (go) versions <= 0.9.0 is affected.
- Is there a fix for CVE-2026-62331? Yes. CVE-2026-62331 is fixed in 0.9.1. Upgrade to this version or later.
- Is CVE-2026-62331 exploitable, and should I be worried? Whether CVE-2026-62331 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-62331 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-62331? Upgrade
github.com/mtzanidakis/praktorto 0.9.1 or later.