UNIX Symbolic Link (Symlink) Following

Apptainer is an open source container platform. In Apptainer versions less than 1.4.5, a container can disable two of the forms of the little used --security option, in particular the forms --security=apparmor:<profile> and --security=selinux:<label> which otherwise put restrictions on operations that containers can do. The --security option has always been mentioned in Apptainer documentation as being a feature for the root user, although these forms do also work for unprivileged users on systems where the corresponding feature is enabled. Apparmor is enabled by default on Debian-based distributions and SElinux is enabled by default on RHEL-based distributions, but on SUSE it depends on the distribution version. This vulnerability is fixed in 1.4.5.Show less

SingularityCE and SingularityPRO are open source container platforms. Prior to SingularityCE 4.3.5 and SingularityPRO 4.1.11 and 4.3.5, if a user relies on LSM restrictions to prevent malicious operations then, under certain circumstances, an attacker can redirect the LSM label write operation so that it is ineffective. The attacker must cause the user to run a malicious container image that redirects the mount of /proc to the destination of a shared mount, either known to be configured on the target system, or that will be specified by the user when running the container. The attacker must also control the content of the shared mount, for example through another malicious container which also binds it, or as a user with relevant permissions on the host system it is bound from. This vulnerability is fixed in SingularityCE 4.3.5 and SingularityPRO 4.1.11 and 4.3.5.Show less

Open OnDemand is an open-source HPC portal. Prior to versions 4.0.8 and 3.1.16, users can craft a "Time of Check to Time of Use" (TOCTOU) attack when downloading zip files to access files outside of the OOD_ALLOWLIST. This vulnerability impacts sites that use the file browser allowlists in all current versions of OOD. However, files accessed are still protected by the UNIX permissions. Open OnDemand versions 4.0.8 and 3.1.16 have been patched for this vulnerability.Show less

runc is a CLI tool for spawning and running containers according to the OCI specification. In versions 1.2.7, 1.3.2 and 1.4.0-rc.2, an attacker can trick runc into misdirecting writes to /proc to other procfs files through the use of a racing container with shared mounts (we have also verified this attack is possible to exploit using a standard Dockerfile with docker buildx build as that also permits triggering parallel execution of containers with custom shared mounts configured). This redirect could be through symbolic links in a tmpfs or theoretically other methods such as regular bind-mounts. While similar, the mitigation applied for the related CVE, CVE-2019-19921, was fairly limited and effectively only caused runc to verify that when LSM labels are written they are actually procfs files. This issue is fixed in versions 1.2.8, 1.3.3, and 1.4.0-rc.3.Show less

runc is a CLI tool for spawning and running containers according to the OCI specification. Versions 1.0.0-rc3 through 1.2.7, 1.3.0-rc.1 through 1.3.2, and 1.4.0-rc.1 through 1.4.0-rc.2, due to insufficient checks when bind-mounting `/dev/pts/$n` to `/dev/console` inside the container, an attacker can trick runc into bind-mounting paths which would normally be made read-only or be masked onto a path that the attacker can write to. This attack is very similar in concept and application to CVE-2025-31133, except that it attacks a similar vulnerability in a different target (namely, the bind-mount of `/dev/pts/$n` to `/dev/console` as configured for all containers that allocate a console). This happens after `pivot_root(2)`, so this cannot be used to write to host files directly -- however, as with CVE-2025-31133, this can load to denial of service of the host or a container breakout by providing the attacker with a writable copy of `/proc/sysrq-trigger` or `/proc/sys/kernel/core_pattern` (respectively). This issue is fixed in versions 1.2.8, 1.3.3 and 1.4.0-rc.3.Show less

runc is a CLI tool for spawning and running containers according to the OCI specification. In versions 1.2.7 and below, 1.3.0-rc.1 through 1.3.1, 1.4.0-rc.1 and 1.4.0-rc.2 files, runc would not perform sufficient verification that the source of the bind-mount (i.e., the container's /dev/null) was actually a real /dev/null inode when using the container's /dev/null to mask. This exposes two methods of attack: an arbitrary mount gadget, leading to host information disclosure, host denial of service, container escape, or a bypassing of maskedPaths. This issue is fixed in versions 1.2.8, 1.3.3 and 1.4.0-rc.3.Show less

Youki is a container runtime written in Rust. In versions 0.5.6 and below, youki’s apparmor handling performs insufficiently strict write-target validation, and when combined with path substitution during pathname resolution, can allow writes to unintended procfs locations. While resolving a path component-by-component, a shared-mount race can substitute intermediate components and redirect the final target. This issue is fixed in version 0.5.7.Show less

Youki is a container runtime written in Rust. In versions 0.5.6 and below, the initial validation of the source /dev/null is insufficient, allowing container escape when youki utilizes bind mounting the container's /dev/null as a file mask. This issue is fixed in version 0.5.7.Show less

SupportAssist for Home PCs versions 4.8.2 and prior and SupportAssist for Business PCs versions 4.5.3 and prior, contain an UNIX Symbolic Link (Symlink) following vulnerability. A low privileged attacker with local access to the system could potentially exploit this vulnerability to delete arbitrary files only in that affected system.Show less

A security vulnerability has been detected in wonderwhy-er DesktopCommanderMCP up to 0.2.13. This vulnerability affects the function isPathAllowed of the file src/tools/filesystem.ts. The manipulation leads to symlink following. The attack can only be performed from a local environment. The attack's complexity is rated as high. It is stated that the exploitability is difficult. The exploit has been disclosed publicly and may be used. The vendor explains: "Our restriction features are designed as guardrails for LLMs to help them stay closer to what users want, rather than hardened security boundaries. (...) For users where security is a top priority, we continue to recommend using Desktop Commander with Docker, which provides actual isolation. (...) We'll keep this issue open for future consideration if we receive more user demand for improved restrictions." This vulnerability only affects products that are no longer supported by the maintainer.Show less

Claude Code is an agentic coding tool. Versions below 1.0.120 failed to account for symlinks when checking permission deny rules. If a user explicitly denied Claude Code access to a file and Claude Code had access to a symlink pointing to that file, it was possible for Claude Code to access the file. Users on standard Claude Code auto-update will have received this fix automatically. Users performing manual updates are advised to update to the latest version. This issue is fixed in version 1.0.120.Show less

tar-fs provides filesystem bindings for tar-stream. Versions prior to 3.1.1, 2.1.3, and 1.16.5 are vulnerable to symlink validation bypass if the destination directory is predictable with a specific tarball. This issue has been patched in version 3.1.1, 2.1.4, and 1.16.6. A workaround involves using the ignore option on non files/directories.Show less

astral-tokio-tar is a tar archive reading/writing library for async Rust. In versions 0.5.3 and earlier of astral-tokio-tar, tar archives may extract outside of their intended destination directory when using the Entry::unpack_in_raw API. Additionally, the Entry::allow_external_symlinks control (which defaults to true) could be bypassed via a pair of symlinks that individually point within the destination but combine to point outside of it. These behaviors could be used individually or combined to bypass the intended security control of limiting extraction to the given directory. This in turn would allow an attacker with a malicious tar archive to perform an arbitrary file write and potentially pivot into code execution. This issue has been patched in version 0.5.4. There is no workaround other than upgrading.Show less

The txtai framework allows the loading of compressed tar files as embedding indices. While the validate function is intended to prevent path traversal vulnerabilities by ensuring safe filenames, it does not account for symbolic links within the tar file. An attacker is able to write a file anywhere in the filesystem when txtai is used to load untrusted embedding indicesShow less

Airlink's Daemon interfaces with Docker and the Panel to provide secure access for controlling instances via the Panel. In version 1.0.0, an attacker with access to the affected container can create symbolic links inside the mounted directory (/app/data). Because the container bind-mounts an arbitrary host path, these symlinks can point to sensitive locations on the host filesystem. When the application or other processes follow these symlinks, the attacker can gain unauthorized read access to host files outside the container. This issue has been patched in version 1.0.1.Show less

Youki is a container runtime written in Rust. Prior to version 0.5.5, if /proc and /sys in the rootfs are symbolic links, they can potentially be exploited to gain access to the host root filesystem. This issue has been patched in version 0.5.5.Show less

Using Codex CLI in workspace-write mode inside a malicious context (repo, directory, etc) could lead to arbitrary file overwrite and potentially remote code execution due to symlinks being followed outside the allowed current working directory.Show less

Improper handling of symbolic links in Ivanti Connect Secure before version 22.7R2.8 or 22.8R2, Ivanti Policy Secure before 22.7R1.5, Ivanti ZTA Gateway before 22.8R2.3-723 and Ivanti Neurons for Secure Access before 22.8R1.4 (Fix deployed on 02-Aug-2025) allows a local authenticated attacker to read arbitrary files on disk.Show less