CVE-2020-14387 [High] | Security Vulnerability in Rsync

A flaw was found in rsync in versions since 3.2.0pre1. Rsync improperly validates certificate with host mismatch vulnerability. A remote, unauthenticated attacker could exploit the flaw by performing a man-in-the-middle attack using a valid certificate for another hostname which could compromise confidentiality and integrity of data transmitted using rsync-ssl. The highest threat from this vulnerability is to data confidentiality and integrity. This flaw affects rsync versions before 3.2.4.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2025-11-21	0.26%	0.14%	-0.11%
2	2025-11-18	0.14%	0.26%	+0.11%
3	2025-09-07	—	0.14%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2025-11-21

0.26%

0.14%

-0.11%

2025-11-18

0.14%

0.26%

+0.11%

2025-09-07

—

0.14%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
7.4	3.1	HIGH	`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:H) Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:H) Serious risk that confidential data gets exposed in a big way. Integrity (I:H) They could widely tamper with or forge data—trust in the data is badly hurt. Availability (A:N) Service keeps running; no real outage angle.	2.2	5.2	[email protected]
5.8	2.0	MEDIUM	`AV:N/AC:M/Au:N/C:P/I:P/A:N` Click to expand Access vector (AV:N) Can be exploited remotely over network reachability. Access complexity (AC:M) Exploitation needs some favorable conditions, but not exceptional ones. Authentication (AU:N) No authentication is required. Confidentiality impact (C:P) Partial confidentiality impact. Integrity impact (I:P) Partial integrity impact. Availability impact (A:N) No availability impact.	8.6	4.9	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

7.4

3.1

HIGH

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N Click to expand

Attack vector (AV:N): Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H): Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N): No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N): Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H): Serious risk that confidential data gets exposed in a big way.
Integrity (I:H): They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N): Service keeps running; no real outage angle.

2.2

5.2

[email protected]

5.8

2.0

MEDIUM

AV:N/AC:M/Au:N/C:P/I:P/A:N Click to expand

Access vector (AV:N): Can be exploited remotely over network reachability.
Access complexity (AC:M): Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N): No authentication is required.
Confidentiality impact (C:P): Partial confidentiality impact.
Integrity impact (I:P): Partial integrity impact.
Availability impact (A:N): No availability impact.

8.6

4.9

[email protected]

OS Trackers for CVE-2020-14387

vendor	priority	summary	link
`alpine`	high	CVE-2020-14387: 1 source package rows (rsync); 5 state rows across 2 repos (3.17-main, edge-main); fixed 5, open 0.	https://security.alpinelinux.org/vuln/CVE-2020-14387
`debian`	not yet assigned	CVE-2020-14387 not yet assigned priority: Debian including 1 source packages (rsync), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5.	https://security-tracker.debian.org/tracker/CVE-2020-14387
`gentoo`	normal	CVE-2020-14387: 1 GLSA(s) (202405-22), 1 atom(s) (net-misc/rsync); latest impact normal.	https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2020-14387
`redhat`	high	—	https://access.redhat.com/security/cve/CVE-2020-14387
`ubuntu`	medium	CVE-2020-14387 medium priority: Ubuntu including 1 source packages (rsync), 5 status rows across 5 suites (bionic, focal, trusty, upstream, xenial): not-affected 4, released 1.	https://ubuntu.com/security/CVE-2020-14387

Affected software / configurations for CVE-2020-14387

Vendor	Product	Version	Raw CPE
samba	rsync	>= 3.2.1, < 3.2.4	cpe:2.3:a:samba:rsync::::::::
samba	rsync	3.2.0	cpe:2.3:a:samba:rsync:3.2.0:-::::::
samba	rsync	3.2.0	cpe:2.3:a:samba:rsync:3.2.0:pre1::::::
samba	rsync	3.2.0	cpe:2.3:a:samba:rsync:3.2.0:pre2::::::
samba	rsync	3.2.0	cpe:2.3:a:samba:rsync:3.2.0:pre3::::::

References for CVE-2020-14387

URL	Tags
https://bugzilla.redhat.com/show_bug.cgi?id=1875549	Issue Tracking Patch Third Party Advisory

URL

CVE-2020-14387

Exploit prediction scoring system (EPSS) score for CVE-2020-14387

Common vulnerability scoring system (CVSS) metrics for CVE-2020-14387

Weakness enumeration for CVE-2020-14387

OS Trackers for CVE-2020-14387

Affected software / configurations for CVE-2020-14387

References for CVE-2020-14387