CVE-2021-3139: In Open-iSCSI tcmu-runner 1.3.x, 1.4.x, and 1.5.x through 1.5.2, xcopy_locate_udev in tcmur_cmd_handler.c lack

This month

HIGH 8.1UPGRADE

CVE-2021-3139 is a high-severity flaw (CVSS 8.1) affecting tcmu-runner. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

In Open-iSCSI tcmu-runner 1.3.x, 1.4.x, and 1.5.x through 1.5.2, xcopy_locate_udev in tcmur_cmd_handler.c lacks a check for transport-layer restrictions, allowing remote attackers to read or write files via directory traversal in an XCOPY request. For example, an attack can occur over a network if the attacker has access to one iSCSI LUN. NOTE: relative to CVE-2020-28374, this is a similar mistake in a different algorithm.

Why this priority

High severity

A fixed release or distro patch exists.

Risk facts

CVSS score	8.1 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	2.7% (top 14%)
CISA exploited list	No
Weakness	CWE-22
Published	2021-01-13
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: tcmu-runner project

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2021-01-13 16:15 UTCPublished CVE record published
2026-06-17 04:04 UTCUpdated Record last modified

tcmu-runner project tcmu-runner UPGRADE

Affected: >= 1.3.0 and <= 1.5.2

Fixed in: newer than 1.5.2

Safe to downgrade to: a release before 1.3.0

1. Check installed version

apt-cache policy tcmu-runner || rpm -q tcmu-runner || tcmu-runner --version

2. UPGRADE to newer than 1.5.2 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade tcmu-runner

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade tcmu-runner

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 1.3.0 (Debian / Ubuntu)

apt-cache madison tcmu-runner sudo apt install tcmu-runner=<VERSION_BEFORE_1.3.0> sudo apt-mark hold tcmu-runner

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list tcmu-runner sudo dnf downgrade tcmu-runner-<VERSION_BEFORE_1.3.0> sudo dnf versionlock add tcmu-runner

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-3139?

tcmu-runner: upgrade to newer than 1.5.2. Exact commands for each OS are on this page.

Is CVE-2021-3139 being exploited?

CVE-2021-3139 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-3139 affect?

CVE-2021-3139 affects tcmu-runner. Severity is high (CVSS 8.1). In Open-iSCSI tcmu-runner 1.3.x, 1.4.x, and 1.5.x through 1.5.2, xcopy_locate_udev in tcmur_cmd_handler.c lacks a check for transport-layer restrictions, allowing remote attackers to read or write files via directory traversal in an XCOPY r

How urgent is CVE-2021-3139?

Priority 50/100. High severity

Related CVEs

CVE-2017-1000201 MEDIUM 5.5 DOWNGRADE The tcmu-runner daemon in tcmu-runner version 1.0.5 to 1.2.0 is vulnerable to a local denial of service attack
CVE-2017-1000200 HIGH 7.5 DOWNGRADE tcmu-runner version 1.0.5 to 1.2.0 is vulnerable to a dbus triggered NULL pointer dereference in the tcmu-runn
CVE-2017-1000199 HIGH 7.5 DOWNGRADE tcmu-runner version 0.91 up to 1.20 is vulnerable to information disclosure in handler_qcow.so resulting in no
CVE-2017-1000198 HIGH 7.5 DOWNGRADE tcmu-runner daemon version 0.9.0 to 1.2.0 is vulnerable to invalid memory references in the handler_glfs.so ha

References

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