Which versions of tar-rs are affected by EUVD-2026-55682?

A symlink-escape vulnerability in tar-rs (versions 0.4.11-0.4.46) enables attackers to exfiltrate arbitrary files from production systems during archiving operations.

Is there a public PoC exploit available for EUVD-2026-55682?

Yes, a public proof-of-concept exploit is available for EUVD-2026-55682. Prioritise patching immediately. EPSS: 0.3%.

How to fix or mitigate EUVD-2026-55682?

Within 24 hours: Identify all systems and processes using tar-rs versions 0.4.11-0.4.46 (particularly CI/CD, backup, and data pipelines); immediately suspend archiving of untrusted sources and apply strict directory-level access controls. Within 7 days: Implement compensating controls-run tar-rs processes with minimal required privileges, reject archives containing symlinks through validation logic, and deploy monitoring for anomalous file access. Within 30 days: Develop an upgrade or migration strategy to alternative archiving libraries; establish architecture guardrails to isolate archiving operations with read-only confinement to intended directory trees pending vendor patch release.

tar-rs EUVD-2026-55682

Q: What is the CVSS score of EUVD-2026-55682?

EUVD-2026-55682 has a CVSS 4.0 base score of 7.1 (High). CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. EPSS exploitation probability: 0.3%.

| CVE-2026-70622 HIGH

Improper Link Resolution Before File Access (CWE-59)

2026-08-10 VulnCheck

GHSA-c2qp-v5vm-7vxf

Information Disclosure Red Hat Tar Rs

7.1

CVSS 4.0 · Vendor: VulnCheck

Severity by source

Vendor (VulnCheck) PRIMARY

7.1 HIGH

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

vuln.today AI

7.7 HIGH

Network vector retained as attacker supplies directory remotely; S:C because exploitation escapes intended source root to read arbitrary filesystem files.

3.1 AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N

4.0 AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

Red Hat

6.5 MEDIUM

qualitative

Primary rating from Vendor (VulnCheck).

CVSS VectorVendor: VulnCheck

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Lifecycle Timeline

Analysis Generated

Aug 10, 2026 - 18:31 vuln.today

CVE Published

Aug 10, 2026 - 17:35 cve.org

HIGH 7.1

DescriptionCVE.org

tar-rs versions 0.4.11 through 0.4.46 contain a symlink escape vulnerability in the Builder::append_dir_all() function that allows attackers to read files outside the intended source root directory by planting symlinks in an attacker-controlled directory. When a privileged process archives an untrusted directory, the function follows symlinks without verifying that resolved targets remain within the source root, causing out-of-bounds files to be included in the archive as regular files and disclosed to the attacker.

AnalysisAI

Symlink escape in tar-rs versions 0.4.11 through 0.4.46 exposes arbitrary host filesystem files when a privileged process archives an attacker-controlled directory using the Builder::append_dir_all() function. The function resolves symbolic links during recursive directory traversal without verifying that resolved target paths remain within the specified source root, causing out-of-bounds files to be silently captured into the archive as regular file entries and disclosed to the attacker. A publicly available proof-of-concept exists; the CVE is not listed in CISA KEV, but low attack complexity combined with high confidentiality impact makes this a meaningful risk for affected Rust-based archiving pipelines.

Technical ContextAI

tar-rs is a Rust crate for reading and writing tar archives, attributed here under the composefs project (CPE: cpe:2.3:a:composefs:tar-rs:*:*:*:*:*:*:*:*). The vulnerable function, Builder::append_dir_all(), performs recursive directory traversal to append all contents to a tar archive. The root cause is CWE-59 (Improper Link Resolution Before File Access - 'Link Following'): during traversal, the function resolves symbolic links encountered in the directory tree without confirming that the resolved absolute path remains inside the caller-supplied source root. On Unix/Linux filesystems, symlinks are filesystem-level pointers to arbitrary paths; following them without bounds-checking during archiving is functionally equivalent to a path traversal attack. The result is that the archive silently includes the contents of files from outside the intended directory scope, presented as regular file entries with no indication that a symlink was followed. This class of symlink-escape vulnerability in archiving libraries is well-documented and has previously appeared in Go, Python, and Java archive implementations.

RemediationAI

No vendor-released patch version is identified at time of analysis; the fix version is not stated in any available reference. The VulnCheck advisory at https://www.vulncheck.com/advisories/tar-rs-symlink-escape-via-append-dir-all and the tar-rs release history on crates.io should be monitored for an updated patched release. Until a patch is available, the primary compensating control is to avoid calling Builder::append_dir_all() on any directory whose symlinks are not fully trusted: pre-archiving validation should traverse the source directory, resolve each symlink's target, and reject or skip any entry whose canonical path falls outside the source root - this adds I/O overhead proportional to directory size but eliminates the disclosure vector entirely. For services that must archive untrusted input, running the archiving process inside a container or chroot with a restricted filesystem view limits the sensitivity of any files that could be captured even if a symlink is followed. Applying Linux capabilities restrictions (dropping CAP_DAC_READ_SEARCH) or seccomp profiles to the archiving process further reduces the blast radius by bounding the attacker's achievable file reads to what the process's effective UID can normally access.