CVE-2023-39960 [Medium] | Security Vulnerability in Nextcloud Server

Nextcloud Server provides data storage for Nextcloud, an open source cloud platform. In Nextcloud Server starting with 25.0.0 and prior to 25.09 and 26.04; as well as Nextcloud Enterprise Server starting with 22.0.0 and prior to 22.2.10.14, 23.0.12.9, 24.0.12.5, 25.0.9, and 26.0.4; missing protection allows an attacker to brute force passwords on the WebDAV API. Nextcloud Server 25.0.9 and 26.0.4 and Nextcloud Enterprise Server 22.2.10.14, 23.0.12.9, 24.0.12.5, 25.0.9, and 26.0.4 contain patches for this issue. No known workarounds are available.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	0.24%	0.57%	+0.34%
2	2025-11-21	0.13%	0.24%	+0.11%
3	2025-11-18	—	0.13%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-15

0.24%

0.57%

+0.34%

2025-11-21

0.13%

0.24%

+0.11%

2025-11-18

—

0.13%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
5.0	3.1	MEDIUM	`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/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:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:L) A normal user session is enough; they don’t have to be admin. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:C) Breaking this can reach past the original component and bite other resources—bigger blast radius. Confidentiality (C:L) Some sensitive info could get out, but not a total data dump. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:N) Service keeps running; no real outage angle.	3.1	1.4	[email protected]
7.5	3.1	HIGH	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/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:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. 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:N) Data isn’t meaningfully altered or forged. Availability (A:N) Service keeps running; no real outage angle.	3.9	3.6	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

5.0

3.1

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/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:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L): A normal user session is enough; they don’t have to be admin.
User interaction (UI:N): Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C): Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L): Some sensitive info could get out, but not a total data dump.
Integrity (I:N): Data isn’t meaningfully altered or forged.
Availability (A:N): Service keeps running; no real outage angle.

3.1

1.4

[email protected]

7.5

3.1

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/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:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
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:N): Data isn’t meaningfully altered or forged.
Availability (A:N): Service keeps running; no real outage angle.

3.9

3.6

[email protected]

Affected software / configurations for CVE-2023-39960

Vendor	Product	Version	Raw CPE
nextcloud	nextcloud_server	>= 22.0.0, < 22.2.10.14	cpe:2.3:a:nextcloud:nextcloud_server:::::enterprise:::*
nextcloud	nextcloud_server	>= 23.0.0, < 23.0.12.9	cpe:2.3:a:nextcloud:nextcloud_server:::::enterprise:::*
nextcloud	nextcloud_server	>= 24.0.0, < 24.0.12.5	cpe:2.3:a:nextcloud:nextcloud_server:::::enterprise:::*
nextcloud	nextcloud_server	>= 25.0.0, < 25.0.9	cpe:2.3:a:nextcloud:nextcloud_server:::::-:::*
nextcloud	nextcloud_server	>= 25.0.0, < 25.0.9	cpe:2.3:a:nextcloud:nextcloud_server:::::enterprise:::*
nextcloud	nextcloud_server	>= 26.0.0, < 26.0.4	cpe:2.3:a:nextcloud:nextcloud_server:::::-:::*
nextcloud	nextcloud_server	>= 26.0.0, < 26.0.4	cpe:2.3:a:nextcloud:nextcloud_server:::::enterprise:::*

References for CVE-2023-39960

URL	Tags
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-2hrc-5fgp-c9c9	Vendor Advisory
https://github.com/nextcloud/server/pull/38046	Issue Tracking Patch
https://hackerone.com/reports/1924212	Third Party Advisory

URL

CVE-2023-39960 | Nextcloud Server has improper restriction of excessive authentication attempts on WebDAV endpoint

Exploit prediction scoring system (EPSS) score for CVE-2023-39960

Common vulnerability scoring system (CVSS) metrics for CVE-2023-39960

Weakness enumeration for CVE-2023-39960

Affected software / configurations for CVE-2023-39960

References for CVE-2023-39960