Tar: tar: --one-top-level hardlink targets not confined to top-level directory enabling arbitrary file overwrite
Priority LOW 19CWE-59Published · Updated
Key facts
- Attack vector
- Local
- Privileges required
- None
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- Low · Low · None
- Fix status
- Partial Red Hat: 6 fixed, 4 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
Summary
A flaw was found in GNU tar. When extracting an archive with the --one-top-level option, hardlink targets are not confined to the designated top-level directory and may resolve relative to the extraction working directory. A crafted archive can create hardlinks that escape the intended boundary and, when combined with a preexisting symbolic link under the working directory, may allow writing outside that boundary during a single extraction.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00141 3rd percentileScored 2026-11-07
Fix Partial Red Hat: 6 advisoriesRed Hat: 6 fixed, 4 without a fix
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Red Hat | Red Hat Enterprise Linux 10 | — | 2:1.35-13.el10_2 | Patch available | CNA |
| Red Hat | Red Hat Enterprise Linux 8 | — | 2:1.30-13.el8_10 | Patch available | CNA |
| Red Hat | Red Hat Enterprise Linux 9 | — | 2:1.34-13.el9_8 | Patch available | CNA |
| Red Hat | Red Hat Discovery 2 | — | 1788205779 | Patch available | CNA |
| Red Hat | Red Hat Hardened Images | — | 1.35-9.2.hum1 | Patch available | CNA |
| Red Hat | Red Hat Update Infrastructure 5 | — | 1788880445 | Patch available | CNA |
| Red Hat | Red Hat Update Infrastructure 5 | — | 1788880464 | Patch available | CNA |
| Red Hat | Red Hat Update Infrastructure 5 | — | 1788880456 | Patch available | CNA |
| Red Hat | Red Hat Update Infrastructure 5 | — | 1788765051 | Patch available | CNA |
| Red Hat | Red Hat Update Infrastructure 5 | — | 1788880581 | Patch available | CNA |
| Red Hat | Red Hat Enterprise Linux 6 | — | — | No fix listed | CNA |
| Red Hat | Red Hat Enterprise Linux 7 | — | — | No fix listed | CNA |
| Red Hat | Red Hat Hardened Images | — | — | Not affected | CNA |
| Red Hat | Red Hat Hardened Images | — | — | Not affected | CNA |
| Red Hat | Red Hat Hardened Images | — | — | Not affected | CNA |
| Red Hat | Red Hat Hardened Images | — | — | Not affected | CNA |
| Red Hat | Red Hat Hardened Images | — | — | Not affected | CNA |
| Red Hat | Red Hat Hardened Images | — | — | Not affected | CNA |
| Red Hat | Red Hat Hardened Images | — | — | Not affected | CNA |
| Red Hat | Red Hat Hardened Images | — | — | Not affected | CNA |
| Red Hat | Red Hat Hardened Images | — | — | Not affected | CNA |
| Red Hat | Red Hat Hardened Images | — | — | Not affected | CNA |
| Red Hat | Red Hat OpenShift Container Platform 4 | — | — | No fix listed | CNA |
| Red Hat | Red Hat OpenShift Container Platform 4 | — | — | No fix listed | CNA |
| Red Hat | Red Hat OpenShift Container Platform 5 | — | — | No fix listed | CNA |
- Red Hat Enterprise Linux 10 VendorRed Hat Affected — Fixed in 2:1.35-13.el10_2 Patch available CNA
- Red Hat Enterprise Linux 8 VendorRed Hat Affected — Fixed in 2:1.30-13.el8_10 Patch available CNA
- Red Hat Enterprise Linux 9 VendorRed Hat Affected — Fixed in 2:1.34-13.el9_8 Patch available CNA
- Red Hat Discovery 2 VendorRed Hat Affected — Fixed in 1788205779 Patch available CNA
- Red Hat Hardened Images VendorRed Hat Affected — Fixed in 1.35-9.2.hum1 Patch available CNA
- Red Hat Update Infrastructure 5 VendorRed Hat Affected — Fixed in 1788880445 Patch available CNA
- Red Hat Update Infrastructure 5 VendorRed Hat Affected — Fixed in 1788880464 Patch available CNA
- Red Hat Update Infrastructure 5 VendorRed Hat Affected — Fixed in 1788880456 Patch available CNA
- Red Hat Update Infrastructure 5 VendorRed Hat Affected — Fixed in 1788765051 Patch available CNA
- Red Hat Update Infrastructure 5 VendorRed Hat Affected — Fixed in 1788880581 Patch available CNA
- Red Hat Enterprise Linux 6 VendorRed Hat Affected — Fixed in — No fix listed CNA
- Red Hat Enterprise Linux 7 VendorRed Hat Affected — Fixed in — No fix listed CNA
- Red Hat Hardened Images VendorRed Hat Affected — Fixed in — Not affected CNA
- Red Hat Hardened Images VendorRed Hat Affected — Fixed in — Not affected CNA
- Red Hat Hardened Images VendorRed Hat Affected — Fixed in — Not affected CNA
- Red Hat Hardened Images VendorRed Hat Affected — Fixed in — Not affected CNA
- Red Hat Hardened Images VendorRed Hat Affected — Fixed in — Not affected CNA
- Red Hat Hardened Images VendorRed Hat Affected — Fixed in — Not affected CNA
- Red Hat Hardened Images VendorRed Hat Affected — Fixed in — Not affected CNA
- Red Hat Hardened Images VendorRed Hat Affected — Fixed in — Not affected CNA
- Red Hat Hardened Images VendorRed Hat Affected — Fixed in — Not affected CNA
- Red Hat Hardened Images VendorRed Hat Affected — Fixed in — Not affected CNA
- Red Hat OpenShift Container Platform 4 VendorRed Hat Affected — Fixed in — No fix listed CNA
- Red Hat OpenShift Container Platform 4 VendorRed Hat Affected — Fixed in — No fix listed CNA
- Red Hat OpenShift Container Platform 5 VendorRed Hat Affected — Fixed in — No fix listed CNA
CPE configurations NVD · 5
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:gnu:tar:1.35:*:*:*:*:*:*:* | 1.35 | Vulnerable | GNU |
| cpe:2.3:a:redhat:openshift_container_platform:4.0:*:*:*:*:*:*:* | 4.0 | Vulnerable | Red Hat |
| cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:* | 8.0 | Vulnerable | Red Hat |
| cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:* | 9.0 | Vulnerable | Red Hat |
| cpe:2.3:o:redhat:enterprise_linux:10.0:*:*:*:*:*:*:* | 10.0 | Vulnerable | Red Hat |
- cpe:2.3:a:gnu:tar:1.35:*:*:*:*:*:*:* Versions 1.35 Vulnerable ·GNU
- cpe:2.3:a:redhat:openshift_container_platform:4.0:*:*:*:*:*:*:* Versions 4.0 Vulnerable ·Red Hat
- cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:* Versions 8.0 Vulnerable ·Red Hat
- cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:* Versions 9.0 Vulnerable ·Red Hat
- cpe:2.3:o:redhat:enterprise_linux:10.0:*:*:*:*:*:*:* Versions 10.0 Vulnerable ·Red Hat
Remediation
Red Hat 6 advisories
- RHSA-2026:70390 Released 2026-09-22 · Red Hat rating Moderatetar security, bug fix, and enhancement update
- Red Hat Enterprise Linux BaseOS (v. 8) tar-2:1.30-13.el8_10
- RHSA-2026:66018 Released 2026-09-09 · Red Hat rating ImportantRed Hat Update Infrastructure 5.3 security update
- Red Hat Update Infrastructure 5 registry.redhat.io/rhui5/cds-kubernetes-rhel9, registry.redhat.io/rhui5/cds-rhel9, registry.redhat.io/rhui5/haproxy-rhel9 +2
- RHSA-2026:61586 Released 2026-09-01 · Red Hat rating Moderatetar security, bug fix, and enhancement update
- Red Hat Enterprise Linux BaseOS (v. 10) tar-2:1.35-13.el10_2
Show 3 more Red Hat advisories
- RHSA-2026:61783 Released 2026-08-31 · Red Hat rating ImportantA Subscription Management tool for finding and reporting Red Hat product usage
- Red Hat Discovery 2 registry.redhat.io/discovery/discovery-server-rhel9, registry.redhat.io/discovery/discovery-ui-rhel9
- RHSA-2026:61581 Released 2026-08-31 · Red Hat rating Moderatetar security, bug fix, and enhancement update
- Red Hat Enterprise Linux BaseOS (v. 9) tar-2:1.34-13.el9_8
- RHSA-2026:50807 Released 2026-08-05 · Red Hat rating ModerateRed Hat Hardened Images RPMs bug fix and enhancement update
- Red Hat Hardened Images tar-2:1.35-9.2.hum1@aarch64, tar-2:1.35-9.2.hum1@src, tar-2:1.35-9.2.hum1@x86_64
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 7 | Affected | No fix planned: Out of support scope |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet: Fix deferred |
| Red Hat Discovery 2 | Fixed | RHSA-2026:61783 |
| Red Hat Enterprise Linux BaseOS (v. 10) | Fixed | RHSA-2026:61586 |
| Red Hat Enterprise Linux BaseOS (v. 8) | Fixed | RHSA-2026:70390 |
| Red Hat Enterprise Linux BaseOS (v. 9) | Fixed | RHSA-2026:61581 |
| Red Hat Hardened Images | Fixed | RHSA-2026:50807 |
| Red Hat Update Infrastructure 5 | Fixed | RHSA-2026:66018 |
Not affected: 2 products
- Red Hat Discovery 2
- Red Hat Hardened Images
Timeline
- 2026-10-02 Threatist record created from CVE-2026-18508
- 2026-10-03 Alias added: GHSA-4f5j-wqjr-hx49
- 2026-10-30 Affected versions changed · CNA
- 2026-10-30 Affected versions changed · Red Hat
References
More Red Hat Enterprise Linux vulnerabilities
- TI-2019-08259 Underflow in PHP-FPM can lead to RCE KEVCVSS 3.1CRITICAL 9.8
- TI-2018-10530 Code injection in [UNKNOWN] RichFaces KEVCVSS 3.1CRITICAL 9.8
- TI-2014-05975 GNU Bash through 4.3 bash43-025 processes trailing strings after certain malformed… KEVCVSS 3.1CRITICAL 9.8
- TI-2014-05157 GNU Bash through 4.3 processes trailing strings after function definitions in the values… KEVCVSS 3.1CRITICAL 9.8
- TI-2025-23530 Sudo before 1.9.17p1 allows local users to obtain root access because /etc/nsswitch.conf… KEVCVSS 3.1CRITICAL 9.3
- TI-2021-17490 mod_proxy SSRF KEVCVSS 3.1CRITICAL 9.0
Sources
- CVE-2026-18508 · CVE Program
- CVE-2026-18508 · NVD
- FIRST EPSS
- GHSA-4f5j-wqjr-hx49 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-18508 · Red Hat security data · CC BY 4.0
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