HOMEVULNERABILITIESCVE-2021-3578
HIGH

CVE-2021-3578

CWE-704Published: February 16, 2022· Updated: Jun 17, 2026

7.8
CVSS v3.1

Official Description

A flaw was found in mbsync before v1.3.6 and v1.4.2, where an unchecked pointer cast allows a malicious or compromised server to write an arbitrary integer value past the end of a heap-allocated structure by issuing an unexpected APPENDUID response. This could be plausibly exploited for remote code execution on the client.

NVD Source

Technical Analysis

CVE-2021-3578 requires local access, meaning attackers must already have a foothold on the target system.

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 7.8.

CVSS v3.1 Vector Breakdown

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

Affected Vendors & Products

Debian1 product(s)
debian linux
Fedora1 product(s)
fedora
isync_project1 product(s)
isync
Source: NVD CPE · 6 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

PATCHhttp://www.openwall.com/lists/oss-security/2021/06/07/1
PATCHhttps://bugzilla.redhat.com/show_bug.cgi?id=1967397
PATCHhttps://www.openwall.com/lists/oss-security/2021/06/07/1
PATCHhttp://www.openwall.com/lists/oss-security/2021/06/07/1
PATCHhttps://bugzilla.redhat.com/show_bug.cgi?id=1967397
PATCHhttps://www.openwall.com/lists/oss-security/2021/06/07/1
ADVISORYhttps://lists.debian.org/debian-lts-announce/2022/07/msg00001.html
ADVISORYhttps://security.gentoo.org/glsa/202208-15
ADVISORYhttps://lists.debian.org/debian-lts-announce/2022/07/msg00001.html
ADVISORYhttps://security.gentoo.org/glsa/202208-15

All References (18)

→
http://www.openwall.com/lists/oss-security/2021/06/07/1Mailing List · Patch · Third Party Advisory
→
https://bugzilla.redhat.com/show_bug.cgi?id=1961710Not Applicable
→
https://bugzilla.redhat.com/show_bug.cgi?id=1967397Issue Tracking · Patch · Third Party Advisory
→
https://github.blog/2021-06-10-privilege-escalation-polkit-root-on-linux-with-bug/Not Applicable
→
https://lists.debian.org/debian-lts-announce/2022/07/msg00001.htmlMailing List · Third Party Advisory
→
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RPIDLIJKNRJHUVBCL7QGAPAAVPIHQGXK/
→
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/U75UFEWRAZYKVL5NHMPBUOLWN3WXTOEI/
→
https://security.gentoo.org/glsa/202208-15Third Party Advisory
→
https://www.openwall.com/lists/oss-security/2021/06/07/1Mailing List · Patch · Third Party Advisory
→
http://www.openwall.com/lists/oss-security/2021/06/07/1Mailing List · Patch · Third Party Advisory
→
https://bugzilla.redhat.com/show_bug.cgi?id=1961710Not Applicable
→
https://bugzilla.redhat.com/show_bug.cgi?id=1967397Issue Tracking · Patch · Third Party Advisory
→
https://github.blog/2021-06-10-privilege-escalation-polkit-root-on-linux-with-bug/Not Applicable
→
https://lists.debian.org/debian-lts-announce/2022/07/msg00001.htmlMailing List · Third Party Advisory
→
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RPIDLIJKNRJHUVBCL7QGAPAAVPIHQGXK/

Quick Facts

CVE IDCVE-2021-3578
CVSS Score7.8 / 10
SeverityHIGH
WeaknessCWE-704
CISA KEVNo
Affected3 vendor(s)
PublishedFeb 16, 2022

Related CVEs (CWE-704)

CVE-2015-3120
10.0
CVE-2020-25576
9.8
CVE-2016-7979
9.8
CVE-2018-4944
9.8
CVE-2020-6151
9.8
CVE-2023-6249
9.8

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2021-3578 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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