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CVE Record

CVE-2026-26158: Busybox: busybox: arbitrary file modification and privilege escalation via unvalidated tar archive entries

A flaw was found in BusyBox. This vulnerability allows an attacker to modify files outside of the intended extraction directory by crafting a malicious tar archive containing unvalidated hardlink or symlink entries. If the tar archive is extracted with elevated privileges, this flaw can lead to privilege escalation, enabling an attacker to gain unauthorized access to critical system files.

HighCVSS 7Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

BusyBox tar can be tricked into changing files outside the intended extraction folder when handling specially crafted archive links. If this happens during privileged extraction, an attacker could alter sensitive files and potentially gain higher system access.

Executive priority

Prioritize remediation where BusyBox is embedded in production images or operational devices and where tar extraction is automated or privileged. This is not currently evidenced as actively exploited, but privilege escalation potential makes it a near-term hardening item.

Technical view

CVE-2026-26158 is a BusyBox archive extraction flaw involving unvalidated hardlink or symlink entries. The issue maps to CWE-73 and is scored CVSS 3.1 7.0. Red Hat lists Red Hat Hardened Images busybox-main 1.37.0-7.2.hum1 as affected, with RHEL 6 busybox status unknown.

Likely exposure

Highest concern is systems, appliances, containers, or build workflows that use BusyBox tar to extract archives, especially when extraction runs as root or another privileged account. The provided affected list is limited to Red Hat data and should not be treated as exhaustive.

Exploitation context

The source bundle does not show known active exploitation, and KEV is false. Exploitation appears local and user-assisted: a crafted tar archive must be extracted, with greater impact when privileged extraction is used.

Researcher notes

Evidence points to unsafe path/link handling during archive extraction. The public bundle identifies Red Hat Hardened Images as affected and RHEL 6 as unknown; broader BusyBox downstream impact requires vendor confirmation. Do not assume all BusyBox builds are affected without advisory support.

Mitigation direction

  • Follow RHSA-2026:13831 and vendor advisories for update guidance.
  • Avoid extracting untrusted tar archives with elevated privileges.
  • Run archive extraction in least-privileged, isolated working directories.
  • Review Siemens advisory if Siemens products are in scope.
  • Track Red Hat VEX status for unknown or deferred products.

Validation and detection

  • Inventory BusyBox and busybox-main versions across hosts, images, and appliances.
  • Check Red Hat Hardened Images for busybox-main 1.37.0-7.2.hum1 exposure.
  • Identify workflows that extract user-supplied archives as root.
  • Confirm whether any Siemens products match SSA-253495.
  • Document compensating controls for privileged archive extraction paths.
Prepared
Confidence
medium
Sources
8

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · medium confidence lookup

CWE-73: File access and web shell behavior lookup

File traversal and upload weaknesses can lead teams to review file, web shell, execution, and collection telemetry. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
description · low confidence lookup

Privilege behavior lookup

The CVE wording references privilege impact, so privilege escalation and authorization behavior review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

Open ATT&CK lookup
description · low confidence lookup

File access behavior lookup

The CVE wording references file access or upload behavior, so file telemetry and web shell review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2026-26158 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
High
CVSS
7 (3.1)
Known Exploited
No
Published

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

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

2CVSS vectors
7Timeline events
3ADP providers
7Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: total

CVSS vector scores

2 official scores

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7CVSS 3.1HighCVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H15.9redhat
7CVSS 3.1HighCVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H15.9redhat-SADP

Vulnerability scoring details

Base CVSS 3.1 score

7High
CVSS 3.1 vector shape for CVE-2026-26158Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. ADP timelineredhat-SADP

    Made public.

  2. Source timelineredhat

    Made public.

  3. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  4. ADP timelineredhat-SADP

    Reported to Red Hat.

  5. Source timelineredhat

    Reported to Red Hat.

  6. CVE publishedCVE Program

    The CVE record was published.

  7. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc
siemens-SADPADP container
redhat-SADPbusybox: BusyBox: Arbitrary file modification and privilege escalation via unvalidated tar archive entries
other:Red Hat severity ratingcvssV3_1
  • 2026-02-11T18:09:00.001Z: Reported to Red Hat.
  • 2026-02-11T00:00:00.000Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
Red HatRed Hat Hardened Imagesbusybox-main, 1.37.0-7.2.hum1affected
Red HatRed Hat Enterprise Linux 6busyboxunknown
Weakness

CWE details

CWE-73

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.