CVE-2021-33910

Name: CVE-2021-33910
Creator: NVD / NIST
Published: 2021-07-20T19:15:09.783+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.5/10EPSS 8.65%

Last modified Jun 17, 2026

CVE-2021-33910 is a medium-severity vulnerability rated 5.5/10 on the CVSS scale. basic/unit-name.c in systemd prior to 246.15, 247.8, 248.5, and 249.1 has a Memory Allocation with an Excessive Size Value (involving strdupa and alloca for a pathname controlled by a local attacker) that results in an operating system crash.. EPSS estimates a 8.65% chance of exploitation in the next 30 days.

Description

basic/unit-name.c in systemd prior to 246.15, 247.8, 248.5, and 249.1 has a Memory Allocation with an Excessive Size Value (involving strdupa and alloca for a pathname controlled by a local attacker) that results in an operating system crash.

Metrics

CVSS 3.1

5.5/10

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

EPSS Probability

8.65%

94.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Systemd Project	Systemd	< 246.15
Systemd Project	Systemd	>= 247, < 247.8
Systemd Project	Systemd	>= 248, < 248.5
Systemd Project	Systemd	>= 249, < 249.1
Fedoraproject	Fedora	33
Fedoraproject	Fedora	34
Debian	Debian Linux	10.0
Netapp	Hci Management Node	All versions
Netapp	Solidfire	All versions

References

http://packetstormsecurity.com/files/163621/Sequoia-A-Deep-Root-In-Linuxs-Filesystem-Layer.htmlExploit, Third Party Advisory, VDB Entry
http://www.openwall.com/lists/oss-security/2021/08/04/2Mailing List, Patch, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/08/17/3Mailing List, Patch, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/09/07/3Mailing List, Patch, Third Party Advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-222547.pdf
https://github.com/systemd/systemd-stable/commit/4a1c5f34bd3e1daed4490e9d97918e504d19733bPatch, Third Party Advisory
https://github.com/systemd/systemd-stable/commit/764b74113e36ac5219a4b82a05f311b5a92136cePatch, Third Party Advisory
https://github.com/systemd/systemd-stable/commit/b00674347337b7531c92fdb65590ab253bb57538Patch, Third Party Advisory
https://github.com/systemd/systemd-stable/commit/cfd14c65374027b34dbbc4f0551456c5dc2d1f61Patch, Third Party Advisory
https://github.com/systemd/systemd/commit/b34a4f0e6729de292cb3b0c03c1d48f246ad896bPatch, Third Party Advisory
https://github.com/systemd/systemd/pull/20256/commits/441e0115646d54f080e5c3bb0ba477c892861ab9Patch, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2LSDMHAKI4LGFOCSPXNVVSEWQFAVFWR7/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/42TMJVNYRY65B4QCJICBYOEIVZV3KUYI/
https://security.gentoo.org/glsa/202107-48Third Party Advisory
https://security.netapp.com/advisory/ntap-20211104-0008/Third Party Advisory
https://www.debian.org/security/2021/dsa-4942Third Party Advisory
https://www.openwall.com/lists/oss-security/2021/07/20/2Exploit, Mailing List, Third Party Advisory
http://packetstormsecurity.com/files/163621/Sequoia-A-Deep-Root-In-Linuxs-Filesystem-Layer.htmlExploit, Third Party Advisory, VDB Entry
http://www.openwall.com/lists/oss-security/2021/08/04/2Mailing List, Patch, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/08/17/3Mailing List, Patch, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/09/07/3Mailing List, Patch, Third Party Advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-222547.pdf
https://github.com/systemd/systemd-stable/commit/4a1c5f34bd3e1daed4490e9d97918e504d19733bPatch, Third Party Advisory
https://github.com/systemd/systemd-stable/commit/764b74113e36ac5219a4b82a05f311b5a92136cePatch, Third Party Advisory
https://github.com/systemd/systemd-stable/commit/b00674347337b7531c92fdb65590ab253bb57538Patch, Third Party Advisory
https://github.com/systemd/systemd-stable/commit/cfd14c65374027b34dbbc4f0551456c5dc2d1f61Patch, Third Party Advisory
https://github.com/systemd/systemd/commit/b34a4f0e6729de292cb3b0c03c1d48f246ad896bPatch, Third Party Advisory
https://github.com/systemd/systemd/pull/20256/commits/441e0115646d54f080e5c3bb0ba477c892861ab9Patch, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2LSDMHAKI4LGFOCSPXNVVSEWQFAVFWR7/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/42TMJVNYRY65B4QCJICBYOEIVZV3KUYI/
https://security.gentoo.org/glsa/202107-48Third Party Advisory
https://security.netapp.com/advisory/ntap-20211104-0008/Third Party Advisory
https://www.debian.org/security/2021/dsa-4942Third Party Advisory
https://www.openwall.com/lists/oss-security/2021/07/20/2Exploit, Mailing List, Third Party Advisory

Timeline

Published: Jul 20, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-33910?

How severe is CVE-2021-33910?

CVE-2021-33910 has a CVSS score of 5.5/10 (MEDIUM severity). The EPSS model estimates a 8.65% probability of exploitation in the next 30 days.

How do I fix CVE-2021-33910?

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-2021-33910?

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

Scan your code now

Source: NVD / NIST