CVE-2021-3480: A flaw was found in slapi-nis in versions before 0.56.7

Q: How do I fix CVE-2021-3480?

slapi-nis: upgrade to 0.56.7; fedora: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2021-3480 being exploited?

CVE-2021-3480 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2021-3480 affect?

CVE-2021-3480 affects slapi-nis, fedora. Severity is high (CVSS 7.5). A flaw was found in slapi-nis in versions before 0.56.7. A NULL pointer dereference during the parsing of the Binding DN could allow an unauthenticated attacker to crash the 389-ds-base directory server. The highest threat from this vulnera

Q: How urgent is CVE-2021-3480?

Priority 51/100. High severity; Remotely exploitable, no login, no user action

This month

HIGH 7.5REMOTEUPGRADEMITIGATE

CVE-2021-3480 is a high-severity flaw (CVSS 7.5) affecting slapi-nis, fedora. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A flaw was found in slapi-nis in versions before 0.56.7. A NULL pointer dereference during the parsing of the Binding DN could allow an unauthenticated attacker to crash the 389-ds-base directory server. The highest threat from this vulnerability is to system availability.

Why this priority

High severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.7% (top 23%)
CISA exploited list	No
Weakness	CWE-476
Published	2021-05-20
Last modified	2026-06-17

Publisher (CNA): Red Hat, Inc. · Vendor: fedoraproject · slapi-nis project

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

Am I affected?

Timeline

2021-05-20 13:15 UTCPublished CVE record published
2026-06-17 04:05 UTCUpdated Record last modified

slapi-nis project slapi-nis UPGRADE

Affected: < 0.56.7

Fixed in: 0.56.7

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy slapi-nis || rpm -q slapi-nis || slapi-nis --version

2. UPGRADE to 0.56.7 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade slapi-nis

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade slapi-nis

Note

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

fedoraproject fedora MITIGATE

Affected: 33 · 34

Fixed in: no fixed release known

Safe to downgrade to: a release before 33

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

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-2021-3480?

slapi-nis: upgrade to 0.56.7; fedora: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-3480 being exploited?

CVE-2021-3480 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-2021-3480 affect?

CVE-2021-3480 affects slapi-nis, fedora. Severity is high (CVSS 7.5). A flaw was found in slapi-nis in versions before 0.56.7. A NULL pointer dereference during the parsing of the Binding DN could allow an unauthenticated attacker to crash the 389-ds-base directory server. The highest threat from this vulnera

How urgent is CVE-2021-3480?

Priority 51/100. High severity; Remotely exploitable, no login, no user action

Related CVEs

CVE-2015-0283 HIGH 7.8 UPGRADE The slapi-nis plug-in before 0.54.2 does not properly reallocate memory when processing user accounts, which a

References

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