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CVE-2026-85731Proof of concept (PoC) published · CISA

oras-go: Arbitrary file write outside file.Store root via symlink-chain bypass in tar extraction (pushDir)

CVSS score

8.8

EPSS probability

%0.7

Risk score

0.1

Published

1 mo ago

Official patch verified

Etkilenen ürün ve sürüm için yayımlanan güvenlik güncellemesini uygulayın.

Impact on My Inventory

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Vulnerability description

DayBreach CVE AI Research

CVE-2026-85731 has vendor, distribution, patch and security-source records on file. We can compare them and prepare an explanation linked to the evidence.

oras-go is a Go library for managing OCI artifacts. Prior to 2.6.2, content/file.Store extraction of OCI layers marked with io.deis.oras.content.unpack=true can write outside the store working directory. The pushDir path through extractTarDirectory and ensureLinkPath validates symlink targets lexically, resolveRelToBase skips its parent-symlink walk for root-level entries, and writeFile follows a terminal symlink when opening a regular file. A malicious archive can therefore create a symlink chain whose lexical target remains inside the extraction root but whose resolved target is an attacker-selected absolute path, then overwrite that target with a same-named regular-file entry even when AllowPathTraversalOnWrite is false. Pulling an attacker-controlled artifact can create or overwrite any file writable by the process and may lead to code execution. This issue is fixed in version 2.6.2.

IMPACT: Affected Products and Software

Affected Products

The following products are affected by CVE-2026-85731 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.

IDVENDORPRODUCTACTION
1oras-projectoras-go View
2gooras.land/oras-go/v2 View
3gooras.land/oras-go/v2 View
Total affected vendors: 2|Products: 3

RED HAT CSAF/VEX: Product Impact Check

Red Hat has not yet published a CSAF/VEX impact record for this CVE. This does not mean “not affected”.

SCORING: CVSS from Multiple Sources

CVSS Scores

The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.

SCOREVERSIONSEVERITYVECTORSOURCE
8.8CVSS V31HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:HNVD
8.8CVSS V3_1HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:HCVE CNA
8.8CVSS 3.x—Vector not publishedGitHub Advisory
0.0CVSS 4.0—Vector not publishedGitHub Advisory

Patch and Remediation Guide

Solution & Remediation Advisory

Patch verified

1 doğrulanmış yama veya düzeltilmiş sürüm kanıtı bulundu.

gitlabgo/oras.land/oras-go/v22.6.2

GitLab Advisory düzeltilmiş sürüm: 2.6.2

gitlab

Upgrade to version 2.6.2 or above.

canonical

Upgrade to version 2.6.2 or above.

Confirm the affected product and version against the source evidence above.
Restrict access to internet-facing services and apply network segmentation.
Apply the official update named in the evidence only to the matching product and version.
Monitor server logs and network endpoints for signs of anomalous execution.

Public exploit and active exploitation status

Verified exploit intelligence

No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.

Weakness Classification and Attack Patterns (CWE & CAPEC)

CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-85731 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-85731 weaknesses.

Attack Vector and Accessibility

ExposureAğ üzerinden
PermissionsGerekmiyor
UserGerekiyor

Official Sources and Advisories

CVSS Vector Radar Chart

8.8 / 10
Attack VectorNetworkComplexityLowPrivilegesNoneUser Interact.RequiredConfidentialityLowIntegrityHighAvailabilityHigh

Vulnerability Scoring Details

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone required
User Interaction—
Confidentiality (Gizlilik)Low
Integrity (Bütünlük)High
Availability (Erişilebilirlik)High

Yama doğrulandı

1 doğrulanmış yama veya düzeltilmiş sürüm kanıtı bulundu.

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Weakness Type (CWE & CAPEC)

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