CVE-2021-3139Network attack vector

Cross-LUN data access via unchecked XCOPY descriptors

Published Jan 13, 2021 · Updated Aug 3, 2024

Path traversal in Open-iSCSI tcmu-runner 1.3.x, 1.4.x, and 1.5.x through 1.5.2 allows remote attackers to read or write files via XCOPY. The xcopy_locate_udev function searches every device managed by the daemon and matches attacker-supplied CSCD identifiers without enforcing transport ACLs. Exploitation requires access to one exposed LUN, knowledge of another backstore's NAA identifier, and both backstores under the same tcmu-runner instance.

CVSS severity8.1
High
EPSS probability2.65%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Path traversal in Open-iSCSI tcmu-runner 1.3.x, 1.4.x, and 1.5.x through 1.5.2 allows remote attackers to read or write files via XCOPY. The xcopy_locate_udev function searches every device managed by the daemon and matches attacker-supplied CSCD identifiers without enforcing transport ACLs. Exploitation requires access to one exposed LUN, knowledge of another backstore's NAA identifier, and both backstores under the same tcmu-runner instance.

The record

CVE
CVE-2021-3139
Published
Jan 13, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-22, T1005, T1565.001
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 13, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.5NIST NVDAV:N/AC:L/Au:S/C:P/I:P/A:N
8.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
T1005Data from Local System
T1565.001Stored Data Manipulation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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