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NVD / CVE Program· CNA redhat

CVE-2026-18477: Tar: tar: toctou in incremental dumpdir 'x' rename handling allows restore path escape

Noroxi assessment

Priority: Monitor (action score 17/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.08% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. A user must open a link or visit a page. Special conditions such as timing or configuration are required.
  • Fixed version: tar (AlmaLinux:10) 2:1.35-13.el10_2; tar (AlmaLinux:8) 2:1.30-13.el8_10; tar (AlmaLinux:9) 2:1.34-13.el9_8.

Low priority for now. Upgrade to tar (AlmaLinux:10) 2:1.35-13.el10_2; tar (AlmaLinux:8) 2:1.30-13.el8_10; tar (AlmaLinux:9) 2:1.34-13.el9_8 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

A TOCTOU (Time-of-Check Time-of-Use) vulnerability in GNU tar's incremental dumpdir 'X' rename handling allows a local attacker with write access to a directory being backed up to influence the restore process if the attacker has access to the system where the restore is being performed. During restoration, files or directories may be created, renamed or overwritten outside the intended extraction directory. This could lead to unauthorized file modification or, in some cases, privilege escalation. Exploitation does not require the attacker to modify or craft the archive, and standard backup and restore workflows—including extracting into a newly created directory without using the -P option do not mitigate the issue.

MediumCVSS 4.4 · v3.1—No exploit Fix available
Published
Aug 3, 2026
Updated
Sep 22, 2026
EPSS
0.0% · 0th percentile

Report tools

JSON

Action score

17

Monitor

Low priority for now.

CVSS
17 / 40 · 4.4 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.0%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · redhat
4.4
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
gnutar
redhatopenshift container platform
redhatenterprise linux

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • gnu tar1.35
  • redhat enterprise linux10.0
  • redhat enterprise linux8.0
  • redhat enterprise linux9.0
  • redhat openshift container platform4.0

Versions reported by the vendor

Affected version ranges reported by the assigning authority (redhat). Independent of NVD's CPE analysis and usually ahead of it.

  • Red Hat Red Hat Discovery 2

    • 1788205779 and laternot affected · rpm

  • Red Hat Red Hat Enterprise Linux 10

    • 2:1.35-13.el10_2 and laternot affected · rpm

  • Red Hat Red Hat Enterprise Linux 6

    • all versionsunknown

  • Red Hat Red Hat Enterprise Linux 7

    • all versionsunknown

  • Red Hat Red Hat Enterprise Linux 8

    • 2:1.30-13.el8_10 and laternot affected · rpm

  • Red Hat Red Hat Enterprise Linux 9

    • 2:1.34-13.el9_8 and laternot affected · rpm

  • Red Hat Red Hat Hardened Images

    • 1.35-9.1.hum1 and laternot affected · rpm
    • all versionsunknown
    • all versionsunknown
    • all versionsunknown
    • all versionsunknown
    • all versionsunknown
    • all versionsunknown
    • all versionsunknown
    • all versionsunknown
    • all versionsunknown

  • Red Hat Red Hat OpenShift Container Platform 4

    • all versionsaffected
    • all versionsaffected

  • Red Hat Red Hat Update Infrastructure 5

    • 1788880445 and laternot affected · rpm
    • 1788880464 and laternot affected · rpm
    • 1788880456 and laternot affected · rpm
    • 1788765051 and laternot affected · rpm
    • 1788880581 and laternot affected · rpm

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
AlmaLinux:10tarbefore 2:1.35-13.el10_22:1.35-13.el10_2
AlmaLinux:8tarbefore 2:1.30-13.el8_102:1.30-13.el8_10
AlmaLinux:9tarbefore 2:1.34-13.el9_82:1.34-13.el9_8
Debian:12tarfrom 0—
Red Hat:enterprise_linux:10.2tarbefore 2:1.35-13.el10_22:1.35-13.el10_2
Red Hat:enterprise_linux:10.2tar-debuginfobefore 2:1.35-13.el10_22:1.35-13.el10_2
Red Hat:enterprise_linux:10.2tar-debugsourcebefore 2:1.35-13.el10_22:1.35-13.el10_2
Red Hat:enterprise_linux:8::baseostarbefore 2:1.30-13.el8_102:1.30-13.el8_10
Red Hat:enterprise_linux:8::baseostar-debuginfobefore 2:1.30-13.el8_102:1.30-13.el8_10
Red Hat:enterprise_linux:8::baseostar-debugsourcebefore 2:1.30-13.el8_102:1.30-13.el8_10
Red Hat:enterprise_linux:9::baseostarbefore 2:1.34-13.el9_82:1.34-13.el9_8
Red Hat:enterprise_linux:9::baseostar-debuginfobefore 2:1.34-13.el9_82:1.34-13.el9_8
Red Hat:enterprise_linux:9::baseostar-debugsourcebefore 2:1.34-13.el9_82:1.34-13.el9_8
Red Hat:hummingbird:1tarbefore 0:1.35-9.1.hum10:1.35-9.1.hum1
Rocky Linux:10tarbefore 2:1.35-13.el10_22:1.35-13.el10_2
Rocky Linux:8tarbefore 2:1.30-13.el8_102:1.30-13.el8_10
Rocky Linux:9tarbefore 2:1.34-13.el9_82:1.34-13.el9_8

Same product

gnu: all records

Other highest-scoring records for the same primary product.

  • CVE-2005-2541Tar 1.15.1 does not properly warn the user when extracting setuid or setgid files, which may allow local users or remote attackers to gain p
    41Plan
  • CVE-2016-6321Directory traversal vulnerability in the safer_name_suffix function in GNU tar 1.14 through 1.29 might allow remote attackers to bypass an i
    35Monitor
  • CVE-2007-4476Buffer overflow in the safer_name_suffix function in GNU tar has unspecified attack vectors and impact, resulting in a "crashing stack."
    34Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2025-45582Jul 11, 2025 · GNU Tar through 1.35 allows file overwrite via directory traversal in crafted TAR archives, with a certain two-step process.
    16Monitor
  • ← EarlierCVE-2026-5704Apr 6, 2026 · Tar: tar: hidden file injection via crafted archives
    22Monitor
  • ← EarlierCVE-2026-18508Aug 3, 2026 · Tar: tar: --one-top-level hardlink targets not confined to top-level directory enabling arbitrary file overwrite
    17Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
azl3 tar 1.35-2 on Azure Linux 3.0—Microsoft (MSRC)
almalinux:tar2:1.34-13.el9_8 · AlmaLinux:9Package registry (OSV)
red hat:tar0:1.35-9.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:tar-debuginfo2:1.34-13.el9_8 · Red Hat:enterprise_linux:9::baseosPackage registry (OSV)
red hat:tar-debugsource2:1.34-13.el9_8 · Red Hat:enterprise_linux:9::baseosPackage registry (OSV)
rocky linux:tar2:1.34-13.el9_8 · Rocky Linux:9Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • A user must open a link or visit a page.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
none
Integrity
high · data or configuration can be modified
Availability
none
Attack vector
Local
Attack complexity
High
Privileges required
Low
User interaction
Required
Scope
Unchanged
Confidentiality impact
None
Integrity impact
High
Availability impact
None

Weakness class (CWE)

CWE-367 · Time-of-check Time-of-use (TOCTOU) Race Condition

CVSS vector

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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (7 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records