HOMEVULNERABILITIESCVE-2021-28041
HIGH

CVE-2021-28041

CWE-415Published: March 5, 2021· Updated: Jun 17, 2026

7.1
CVSS v3.1

Official Description

ssh-agent in OpenSSH before 8.5 has a double free that may be relevant in a few less-common scenarios, such as unconstrained agent-socket access on a legacy operating system, or the forwarding of an agent to an attacker-controlled host.

NVD Source

Technical Analysis

CVE-2021-28041 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 7.1.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityHigh
Privileges Req.Low
User InteractionRequired
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H

Affected Vendors & Products

Fedora1 product(s)
fedora
netapp7 product(s)
cloud backuphci management nodesolidfirehci compute node firmwarehci compute nodehci storage node firmwarehci storage node
openbsd1 product(s)
openssh
Oracle2 product(s)
communications offline mediation controllerzfs storage appliance
Source: NVD CPE · 12 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

PATCHhttps://github.com/openssh/openssh-portable/commit/e04fd6dde16de1cdc5a4d9946397ff60d96568db
PATCHhttps://www.openwall.com/lists/oss-security/2021/03/03/1
PATCHhttps://github.com/openssh/openssh-portable/commit/e04fd6dde16de1cdc5a4d9946397ff60d96568db
PATCHhttps://www.openwall.com/lists/oss-security/2021/03/03/1
ADVISORYhttps://security.gentoo.org/glsa/202105-35
ADVISORYhttps://security.netapp.com/advisory/ntap-20210416-0002/
ADVISORYhttps://www.openssh.com/security.html
ADVISORYhttps://www.openssh.com/txt/release-8.5
ADVISORYhttps://www.oracle.com//security-alerts/cpujul2021.html
ADVISORYhttps://security.gentoo.org/glsa/202105-35
ADVISORYhttps://security.netapp.com/advisory/ntap-20210416-0002/
ADVISORYhttps://www.openssh.com/security.html
ADVISORYhttps://www.openssh.com/txt/release-8.5
ADVISORYhttps://www.oracle.com//security-alerts/cpujul2021.html

All References (18)

→
https://github.com/openssh/openssh-portable/commit/e04fd6dde16de1cdc5a4d9946397ff60d96568dbPatch · Third Party Advisory
→
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/KQWGII3LQR4AOTPPFXGMTYE7UDEWIUKI/
→
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TXST2CML2MWY3PNVUXX7FFJE3ATJMNVZ/
→
https://security.gentoo.org/glsa/202105-35Third Party Advisory
→
https://security.netapp.com/advisory/ntap-20210416-0002/Third Party Advisory
→
https://www.openssh.com/security.htmlNot Applicable · Vendor Advisory
→
https://www.openssh.com/txt/release-8.5Release Notes · Vendor Advisory
→
https://www.openwall.com/lists/oss-security/2021/03/03/1Mailing List · Patch · Third Party Advisory
→
https://www.oracle.com//security-alerts/cpujul2021.htmlThird Party Advisory
→
https://github.com/openssh/openssh-portable/commit/e04fd6dde16de1cdc5a4d9946397ff60d96568dbPatch · Third Party Advisory
→
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/KQWGII3LQR4AOTPPFXGMTYE7UDEWIUKI/
→
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TXST2CML2MWY3PNVUXX7FFJE3ATJMNVZ/
→
https://security.gentoo.org/glsa/202105-35Third Party Advisory
→
https://security.netapp.com/advisory/ntap-20210416-0002/Third Party Advisory
→
https://www.openssh.com/security.htmlNot Applicable · Vendor Advisory

Quick Facts

CVE IDCVE-2021-28041
CVSS Score7.1 / 10
SeverityHIGH
WeaknessCWE-415
CISA KEVNo
Affected4 vendor(s)
PublishedMar 5, 2021

Related CVEs (CWE-415)

CVE-2018-0101
10.0
CVE-2021-36088
9.8
CVE-2020-35862
9.8
CVE-2020-35885
9.8
CVE-2019-25009
9.8
CVE-2021-0397
9.8

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2021-28041 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWatch. CVE data is provided under the NVD usage policy.
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