CVE-2026-96620 is a critical vulnerability in the anthropics claude-agent-sdk-python prior to version 0.2.121. The issue arises from improper input validation of the resume option passed to the Claude CLI, allowing an attacker to inject CLI flags such as --mcp-config. This can lead to arbitrary command execution at CLI startup, bypassing SDK permission controls. The vulnerability is fixed in version 0.2.121.
The plugin install flow in Claude Code and Claude Desktop checked out a marketplace's pinned commit SHA using `git checkout` without verifying that the resulting HEAD matched the pinned SHA. An attacker controlling a plugin's upstream repository could create a branch named identically to the pinned 40-character SHA, causing the checkout to silently resolve to the attacker's branch tip instead of the reviewed commit, resulting in attacker-controlled code being installed bypassing the pinned hash. Exploitation required a user to install a malicious plugin, pin to a safe hash, and for the plugin source to be hosted on a git host that permitted SHA-shaped branch names.
Users on standard Claude Code auto-update have received this fix already. Users performing manual updates are advised to update to the latest version.
Thank you to Or Nevo Michrowski of Air Security for reporting this issue.
Claude Code Action is a general-purpose GitHub action that runs Claude Code on GitHub pull requests and issues. Prior to 1.0.74, because the action checked out attacker-controlled pull request head branches, read .mcp.json from the working directory via default setting sources, and unconditionally enabled all project MCP servers via enableAllProjectMcpServers, an attacker who opened a pull request containing a malicious .mcp.json file could achieve arbitrary code execution on the GitHub Actions runner and exfiltrate secrets available to the workflow (such as API keys and tokens) when a privileged user or an automatic trigger invoked the Claude action on the pull request. This issue is fixed in version 1.0.74, which restores .claude/ and .mcp.json from the pull request base branch before the CLI runs.
Buffa is a pure-Rust Protocol Buffers implementation with first-class protobuf editions support. Prior to 0.8.0, the decode_unknown_field function in buffa's protobuf decoder allocated heap memory in proportion to untrusted input (unknown fields in the serialized protobuf) without enforcing an allocation budget, affecting any message decoded from untrusted input using code generated with preserve_unknown_fields=true (the default); a small, well-formed payload of nested unknown fields inside a StartGroup could trigger roughly 22x memory amplification (for example a 64 MiB input forcing about 1.4 GB of heap allocation), and length-delimited unknown fields could be sized arbitrarily, so an unauthenticated attacker could crash a process through memory exhaustion because the top-level message size cap did not account for in-decode amplification. This issue is fixed in version 0.8.0.
Buffa is a pure-Rust Protocol Buffers implementation with first-class protobuf editions support. Prior to 0.7.0, a soundness bug in the OwnedView<V> type allowed safe Rust code to trigger a use-after-free: the OwnedView::decode constructor transmuted a borrowed slice to &'static [u8], and the Deref implementation exposed the promoted 'static lifetime on borrowed view fields (such as &'static str and &'static [u8]) to callers, so the borrow checker permitted those references to outlive the OwnedView; once the OwnedView was dropped and its backing buffer freed, the references became dangling, enabling memory corruption, information disclosure of freed heap contents, and cross-thread misuse without any unsafe code in the calling application. This issue is fixed in version 0.7.0.
Claude Code is an agentic coding tool. From 2.1.38 until 2.1.163, Claude Code's worktree handling allowed creation of worktrees named ".git" and navigation to worktrees outside the sandbox context, enabling git directory confusion attacks. By exploiting symlink manipulation and git fsmonitor execution during worktree operations, an attacker could overwrite files in the user's home directory (such as .zshenv), leading to code execution outside of seatbelt sandbox restrictions. Reliably exploiting this required the user to clone a malicious repository containing prompt injection content and run Claude Code against it. This vulnerability is fixed in 2.1.163.
Claude Code is an agentic coding tool. From 2.1.59 until 2.1.128, the Claude Code /copy command wrote responses to a hardcoded, predictable path (/tmp/claude/response.md) without UID isolation, randomness, or symlink protection. The file was created world-readable (0644) in a world-traversable directory (0755), allowing any local user to read a privileged user's Claude response, which could contain secrets or credentials. Additionally, because the path was static and predictable, a local attacker could pre-create the directory and plant a symlink at the expected file path, causing the privileged process to follow the symlink and overwrite an attacker-chosen file with the response text. Exploiting this required a local unprivileged user on the same system and a privileged user to run the /copy command. This vulnerability is fixed in 2.1.128.
Claude Code is an agentic coding tool. From 0.2.54 until 2.1.163, because the hostname huggingface.co was pre-approved as a bare hostname for the WebFetch tool, any path on that domain—including attacker-controlled model repositories—was auto-approved without a permission prompt or being subject to --allowedTools restrictions. An attacker able to inject untrusted content into a Claude Code context could direct it to issue WebFetch requests against attacker-controlled repository files (e.g. /resolve/main/config.json), which HuggingFace counts as downloads server-side, creating a covert out-of-band channel for encoding and exfiltrating data Claude can access such as files, environment variables, or command output. Reliably exploiting this required the ability to add untrusted content into a Claude Code context window. This vulnerability is fixed in 2.1.163.
CVE-2026-44470 is a local privilege escalation vulnerability in the anthropics claude-code Desktop app for Windows prior to version 1.3834.0. The CoworkVMService component runs as SYSTEM and improperly handles NTFS directory junctions when creating files in the VM bundle directory. A local non-elevated user can exploit this by replacing the VM bundle directory with a junction to an attacker-controlled location, causing SYSTEM-level files to be created arbitrarily. This vulnerability allows escalation from a low-privileged user to SYSTEM privileges. The issue is fixed starting with version 1.3834.0. No known exploits in the wild have been reported.
The Claude Desktop app gives you Claude Code with a graphical interface built for running multiple sessions side by side. From 1.2581.0 to before 1.4304.0, Claude Desktop's SSH remote development feature verified only whether a hostname existed in ~/.ssh/known_hosts without comparing the server's presented host key against the stored key. This allowed a network-positioned attacker to present an arbitrary SSH host key and have the connection silently accepted, enabling a man-in-the-middle attack on remote development sessions. Successful exploitation required the attacker to be in a network position to intercept SSH traffic (e.g., via ARP spoofing, rogue Wi-Fi, or DNS poisoning) and the target hostname to already have an entry in the victim's known_hosts file. This vulnerability is fixed in 1.4304.0.
CVE-2026-40068 is a high-severity vulnerability in anthropics Claude Code versions 2.1.63 through 2.1.83. The issue arises from improper input validation of the git worktree commondir file used in folder trust determination logic. An attacker can craft a malicious repository with a commondir file that points to a path the victim has previously trusted, causing Claude Code to bypass its trust confirmation dialog and execute hooks defined in . claude/settings.json without user consent. Exploitation requires the victim to clone the malicious repository and run Claude Code within it, and the attacker must know or guess a trusted path on the victim's system.
The Claude SDK for TypeScript versions from 0.79.0 up to but not including 0.91.1 had a vulnerability where memory files and directories were created with overly permissive default permissions. This allowed local attackers on shared hosts to read sensitive persisted agent state and, in containerized environments with permissive umasks, to modify these files potentially influencing model behavior. The issue was addressed in version 0.91.1.
Claude Code versions prior to 2.1.64 contain a path traversal vulnerability in their sandbox implementation. The sandbox did not prevent sandboxed processes from creating symbolic links pointing outside the workspace. When the unsandboxed process wrote to a path through such a symlink, it could write outside the intended sandbox without user confirmation. This combination allows sandbox escape and potential code execution outside the sandbox. Exploitation requires injecting untrusted content to trigger sandboxed code execution. Users with standard auto-updates have received the fix; manual update to version 2.1.64 or later is advised.
Claude Code is an agentic coding tool. In versions prior to 2.1.75 on Windows, Claude Code loaded the system-wide default configuration from C:\ProgramData\ClaudeCode\managed-settings.json without validating directory ownership or access permissions. Because the ProgramData directory is writable by non-administrative users by default and the ClaudeCode subdirectory was not pre-created or access-restricted, a low-privileged local user could create this directory and place a malicious configuration file that would be automatically loaded for any user launching Claude Code on the same machine. Exploiting this would have required a shared multi-user Windows system and a victim user to launch Claude Code after the malicious configuration was placed. This issue has been fixed on version 2.1.75.
The async local filesystem memory tool in the Anthropic Python SDK validated that model-supplied paths resolved inside the sandboxed memory directory, but then returned the unresolved path for subsequent file operations. A local attacker able to write to the memory directory could retarget a symlink between validation and use, causing reads or writes to escape the sandbox. The synchronous memory tool implementation was not affected.
Users on the affected versions are advised to update to the latest version.
Claude SDK for Python thanks [hackerone.com/kasthelord](https://hackerone.com/kasthelord) for reporting this issue!
The local filesystem memory tool in the Anthropic Python SDK created memory files with mode 0o666, leaving them world-readable on systems with a standard umask and world-writable in environments with a permissive umask such as many Docker base images. A local attacker on a shared host could read persisted agent state, and in containerized deployments could modify memory files to influence subsequent model behavior. Both the synchronous and asynchronous memory tool implementations were affected.
Users on the affected versions are advised to update to the latest version.
Claude SDK for Python thanks [`lucasfutures`](https://hackerone.com/lucasfutures) on HackerOne for the report.
Claude SDK for TypeScript provides access to the Claude API from server-side TypeScript or JavaScript applications. From version 0.79.0 to before version 0.81.0, the local filesystem memory tool in the Anthropic TypeScript SDK validated model-supplied paths using a string prefix check that did not append a trailing path separator. A model steered by prompt injection could supply a crafted path that resolved to a sibling directory sharing the memory root's name as a prefix, allowing reads and writes outside the sandboxed memory directory. This issue has been patched in version 0.81.0.
Claude Code is an agentic coding tool. Versions prior to 2.1.53 resolved the permission mode from settings files, including the repo-controlled .claude/settings.json, before determining whether to display the workspace trust confirmation dialog. A malicious repository could set permissions.defaultMode to bypassPermissions in its committed .claude/settings.json, causing the trust dialog to be silently skipped on first open. This allowed a user to be placed into a permissive mode without seeing the trust confirmation prompt, making it easier for an attacker-controlled repository to gain tool execution without explicit user consent. This issue has been patched in version 2.1.53.
Claude Code is an agentic coding tool. Prior to version 2.1.2, Claude Code's bubblewrap sandboxing mechanism failed to properly protect the .claude/settings.json configuration file when it did not exist at startup. While the parent directory was mounted as writable and .claude/settings.local.json was explicitly protected with read-only constraints, settings.json was not protected if it was missing. This allowed malicious code running inside the sandbox to create this file and inject persistent hooks (such as SessionStart commands) that would execute with host privileges when Claude Code was restarted. This issue has been patched in version 2.1.2.
Claude Code is an agentic coding tool. Prior to version 2.1.7, Claude Code failed to strictly enforce deny rules configured in settings.json when accessing files through symbolic links. If a user explicitly denied Claude Code access to a file (such as /etc/passwd) and Claude Code had access to a symbolic link pointing to that file, it was possible for Claude Code to read the restricted file through the symlink without triggering deny rule enforcement. This issue has been patched in version 2.1.7.