CVE-2021-39295: In OpenBMC 2.9, crafted IPMI messages allow an attacker to cause a denial of service to the BMC via the netipm

This week

HIGH 7.5REMOTEDOWNGRADE

CVE-2021-39295 is a high-severity flaw (CVSS 7.5) affecting openbmc. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

In OpenBMC 2.9, crafted IPMI messages allow an attacker to cause a denial of service to the BMC via the netipmid (IPMI lan+) interface.

Why this priority

High severity
Public exploit reference
Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.3% (top 30%)
CISA exploited list	No
Weakness	CWE-400
Published	2023-04-15
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: openbmc-project

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

Am I affected?

Timeline

2023-04-15 20:16 UTCPublished CVE record published
2026-06-17 04:03 UTCUpdated Record last modified

openbmc-project openbmc DOWNGRADE

Affected: 2.9.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.9.0

1. Check installed version

apt-cache policy openbmc || rpm -q openbmc || openbmc --version

2. No fixed release: DOWNGRADE to a release before 2.9.0 (Debian / Ubuntu)

apt-cache madison openbmc sudo apt install openbmc=<VERSION_BEFORE_2.9.0> sudo apt-mark hold openbmc

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list openbmc sudo dnf downgrade openbmc-<VERSION_BEFORE_2.9.0> sudo dnf versionlock add openbmc

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-2021-39295?

openbmc: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-39295 being exploited?

CVE-2021-39295 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-2021-39295 affect?

CVE-2021-39295 affects openbmc. Severity is high (CVSS 7.5). In OpenBMC 2.9, crafted IPMI messages allow an attacker to cause a denial of service to the BMC via the netipmid (IPMI lan+) interface.

How urgent is CVE-2021-39295?

Priority 54/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

Related CVEs

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CVE-2024-31916 HIGH 7.5 UPGRADE IBM OpenBMC FW1050.00 through FW1050.10 BMCWeb HTTPS server component could disclose sensitive URI content to
CVE-2023-32280 MEDIUM 5.3 UPGRADE Insufficiently protected credentials in some Intel(R) Server Product OpenBMC firmware before versions egs-1.05

References

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