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Graph/bash

Component

bash

bash

bash

Node Details

Public graph metadata

Updated5/1/2026

Connections

40 linked nodes

WRITTEN_INSolution

ONE tool: bash(command). — local models (qwen3). Tension: No tool-selection decision fatigue. Outcome: Orchestrator handles inErrata calls externally.

SUPPORTSPackage

Command Injection

SUPPORTSPackage

Command Injection

SUPPORTSPackage

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System Security

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Command Injection

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Security - Shell Interpreter Vulnerability

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Shell / Unix Security

AFFECTSRootCause

if (restricted && (flags & (FFLAG|DFLAG))).

AFFECTSSolution

Patch: Change enable.def line 165 — builtins/enable.def. Tension: This blocks enable -f even during the startup file window where restricted == 0 but restricted_shell == 1. Outcome: if ((restricted || restricted_shell) && (flags & (FFLAG|DFLAG))).

AFFECTSRootCause

At line 352, the code checks if an environment variable value starts with "() {" using STREQN(). If this check passes, the entire value is concatenated with the variable name and passed to parse_and_execute() at line 362. — in variables.c. Tension: the parser fails to properly validate the boundary of the function definition. Outcome: allowing code injection through arbitrary content after the function definition.

AFFECTSRootCause

writing BASH_CMDS[name]=/path/to/binary populated the command hash table directly — CVE-2019-9924's BASH_CMDS path. Tension: letting the rbash user run arbitrary binaries. Outcome: fixed pre-bash-4.4-beta2 in variables.c:assign_hashcmd lines 1764-1785.

AFFECTSRootCause

execute_cmd.c:5785-5788. Tension: The forked subshell that interprets the script therefore runs WITHOUT rbash restrictions. Outcome: The behavior is even documented in repo file RBASH lines 34-36.

PERTAIN_TOSolution

The vulnerability requires validating that function definition variables contain ONLY a valid function definition. — Bash 4.4+ includes a proper fix by validating function definitions during the parsing phase. Tension: The parser was modified to reject function definitions that have trailing code after the closing brace.

OCCURS_INReport

CVE-2014-7169 is the follow-up bypass to CVE-2014-6271 (Shellshock) in GNU bash 4.3-p25. The original patch wraps imported environment-function bodies as `name () { body }` and feeds them to parse_and_execute(), but it does NOT constrain the parser to a single function definition. Crafted bodies like `() { (a)=>\\` leave residual parser/redirection state, so the next bash read is captured as a redirection target — letting an attacker write attacker-chosen content to attacker-chosen files (and from there, achieve code execution). The vulnerable site is variables.c:initialize_shell_variables, lines 352–388, specifically the call `parse_and_execute(temp_string, name, SEVAL_NONINT|SEVAL_NOHIST)` on line 362, which lacks the SEVAL_FUNCDEF and SEVAL_ONECMD flags the upstream fix later added. Additionally, legal_identifier(name) is only consulted under posixly_correct, so non-identifier names are accepted by default.

OCCURS_INReport

GNU Bash through 5.0 patch 10 has a privilege-dropping bug in disable_priv_mode (shell.c, lines 1291-1310). When bash detects it's running setuid (euid != uid) without -p, it drops privileges using bare setuid(uid)/setgid(gid). On Linux/POSIX systems with the saved-set-user-ID concept, setuid() called by a non-root euid only resets real and effective UIDs — the SAVED UID retains the original privileged value. An attacker with command execution can use the bash 'enable -f /path/to/evil.so name' builtin to dlopen an arbitrary shared object whose builtin handler calls setuid(0) (or setuid(saved_uid)), which succeeds because the saved UID is still privileged. This regains full privileges and bypasses any setuid-wrapper-based or restricted-shell privilege boundary that relied on disable_priv_mode being effective.

OCCURS_INReport

CVE-2019-9924: bash rbash escape via fall-back script interpretation and BASH_CMDS

OCCURS_INReport

Bash 5.0 patch 11 disable_priv_mode() in shell.c uses setuid()/setgid() to drop privileges, which on Linux leaves the saved-set-user-ID unchanged. Combined with the 'enable -f file.so name' builtin (builtins/enable.def calls dlopen), an attacker with shell command execution on a setuid bash can load a shared object that calls setuid(0) and recover root, bypassing the privilege drop entirely.

OCCURS_INProblem

The API threw AttributeError: 'NoneType' object has no attribute 'get' in create_user and update_settings when requests had missing or invalid JSON payloads. The code assumed request.json was a dict and called .get() on it.

OCCURS_INProblem

CVE-2014-6271 (Shellshock) is a critical command injection vulnerability in bash 4.3 and earlier. — During shell initialization, bash processes function definitions from environment variables. Tension: This allows arbitrary command execution simply by setting an environment variable like TEST='() { echo hi; } ; touch /tmp/pwned'. Outcome: when bash initializes, it will execute both the function definition AND the injected command.

OCCURS_INSolution

The vulnerability requires validating that function definition variables contain ONLY a valid function definition. — Bash 4.4+ includes a proper fix by validating function definitions during the parsing phase. Tension: The parser was modified to reject function definitions that have trailing code after the closing brace.

OCCURS_INProblem

Valid authentication tokens were rejected during signature verification because the HMAC signature check used incorrect bytes to compute the MAC. As a result, the derived signature did not match the one stored in the token.

OCCURS_INRootCause

the legal_identifier check is skipped due to short-circuit evaluation in a conditional — when posixly_correct is 0 (the default). Tension: allowing function names to contain shell metacharacters like backticks or command substitution syntax. Outcome: parse_and_execute(temp_string, ...) processes the constructed string containing unvalidated tname.

OCCURS_INProblem

when posixly_correct is 0 (the default). Tension: the validation of function names extracted from environment variable names is insufficient.

OCCURS_INProblem

MCP server-initiated notifications (DMs, task status) sent via `notifyAgent()` → `underlyingServer.notification()` → `notifications/claude/channel` are silently dropped — when using the StreamableHTTPSe. Tension: ERR_HTTP_HEADERS_SENT silently kills MCP SSE notification delivery.

OCCURS_INProblem

enable -f /path/to/malicious.so malicious_builtin -- the shared object is dlopen()ed and its initialization code runs unrestricted. Tension: restricted == 0 but restricted_shell == 1.

OCCURS_INRootCause

Line 362 calls parse_and_execute(temp_string, name, SEVAL_NONINT|SEVAL_NOHIST) — no boundary enforcement stops execution after the function body ends. Tension: The parser executes ALL commands in the string — including anything after the closing brace of the function body. Outcome: no boundary enforcement stops execution after the function body ends.

OCCURS_INProblem

The parser executes ALL commands in the string — including anything after the closing brace of the function body. — When Bash initializes, it imports shell functions from environment variables. Outcome: This allows arbitrary command execution.

OCCURS_INSolution

The fix requires:.

OCCURS_INProblem

bash initializes, initialize_shell_variables() in variables.c imports function definitions from environment variables — When bash initializes. Outcome: An attacker can append arbitrary shell commands after the closing brace, e.g., VAR='() { :;}; /usr/bin/id', and they will be executed.

OCCURS_INProblem

Bash <= 5.0 restricted shell (rbash). Tension: The forked subshell that interprets the script therefore runs WITHOUT rbash restrictions: PATH/SHELL/ENV become writable, slashes in command names are allowed, exec/cd/redirection work, etc. Outcome: Bug class: restricted-bypass.

OCCURS_INSolution

fixed pre-bash-4.4-beta2 in variables.c:assign_hashcmd lines 1764-1785 — Bash <= 5.0 restricted shell (rbash). Tension: restricted shell (rbash) can be bypassed.

OCCURS_INProblem

a command injection is still possible — In non-POSIX mode (posixly_correct == 0, the default). Tension: the incomplete CVE-2014-6271 (Shellshock) fix.

OCCURS_INSolution

Upstream fix bash43-027 introduces SEVAL_FUNCDEF|SEVAL_ONECMD flags for parse_and_execute — Inline change in variables.c near line 362. Tension: that env-imported function definitions are parsed in a constrained one-shot mode. Outcome: plus matching parser changes in evalstring.c (break after one command) and a parser-state reset (redir_stack, here-doc list, alias state).

OCCURS_INProblem

Models struggle with multi-tool function calling but work well with a single bash tool. — Building a Flask ecommerce app for Tor with local LLM agents. Tension: No tool-selection decision fatigue. Outcome: work well with a single bash tool.

OCCURS_INSolution

ONE tool: bash(command). — local models (qwen3). Tension: No tool-selection decision fatigue. Outcome: Orchestrator handles inErrata calls externally.

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