CVE-2021-20277

Name: CVE-2021-20277
Creator: NVD / NIST
Published: 2021-05-12T14:15:11.14+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 4.33%

Last modified Jun 17, 2026

CVE-2021-20277 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. A flaw was found in Samba's libldb. Multiple, consecutive leading spaces in an LDAP attribute can lead to an out-of-bounds memory write, leading to a crash of the LDAP server process handling the request. EPSS estimates a 4.33% chance of exploitation in the next 30 days.

Description

A flaw was found in Samba's libldb. Multiple, consecutive leading spaces in an LDAP attribute can lead to an out-of-bounds memory write, leading to a crash of the LDAP server process handling the request. The highest threat from this vulnerability is to system availability.

Metrics

CVSS 3.1

7.5/10

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

EPSS Probability

4.33%

89.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Samba	Samba	>= 4.0.0, < 4.12.13
Samba	Samba	>= 4.13.0, < 4.13.6
Samba	Samba	>= 4.14.0, < 4.14.1
Debian	Debian Linux	9.0
Debian	Debian Linux	10.0
Fedoraproject	Fedora	32
Fedoraproject	Fedora	33
Fedoraproject	Fedora	34

References

https://bugzilla.redhat.com/show_bug.cgi?id=1941402Issue Tracking, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/03/msg00036.htmlMailing List, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VLZ74IF2N75VQSIHBL4B3P5WKWQCXSRY/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/X5J3B6PN5XMXF3OHYBNHDKZ3XFSUGY4L/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZXP3ONIY6MB4C5LDZV4YL5KJCES3UX24/
https://security.gentoo.org/glsa/202105-22Third Party Advisory
https://security.netapp.com/advisory/ntap-20210326-0007/Third Party Advisory
https://www.debian.org/security/2021/dsa-4884Third Party Advisory
https://www.samba.org/samba/security/CVE-2021-20277.htmlVendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=1941402Issue Tracking, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/03/msg00036.htmlMailing List, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VLZ74IF2N75VQSIHBL4B3P5WKWQCXSRY/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/X5J3B6PN5XMXF3OHYBNHDKZ3XFSUGY4L/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZXP3ONIY6MB4C5LDZV4YL5KJCES3UX24/
https://security.gentoo.org/glsa/202105-22Third Party Advisory
https://security.netapp.com/advisory/ntap-20210326-0007/Third Party Advisory
https://www.debian.org/security/2021/dsa-4884Third Party Advisory
https://www.samba.org/samba/security/CVE-2021-20277.htmlVendor Advisory

Timeline

Published: May 12, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-20277?

How severe is CVE-2021-20277?

CVE-2021-20277 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 4.33% probability of exploitation in the next 30 days.

How do I fix CVE-2021-20277?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-20277?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST