CVE-2017-16857 [High] | Security Bypass in Bitbucket Auto Unapprove Plugin

It is possible to bypass the bitbucket auto-unapprove plugin via minimal brute-force because it is relying on asynchronous events on the back-end. This allows an attacker to merge any code into unsuspecting repositories. This affects all versions of the auto-unapprove plugin, however since the auto-unapprove plugin is not bundled with Bitbucket Server it does not affect any particular version of Bitbucket.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	0.29%	0.59%	+0.30%
2	2025-03-30	0.57%	0.29%	-0.28%
3	2025-03-29	—	0.57%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-15

0.29%

0.59%

+0.30%

2025-03-30

0.57%

0.29%

-0.28%

2025-03-29

—

0.57%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
8.5	3.0	HIGH	`CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H` 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: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: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:H) Could take the service down hard or make it unusable for people who depend on it.	1.8	6.0	[email protected]
6.0	2.0	MEDIUM	`AV:N/AC:M/Au:S/C:P/I:P/A:P` 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:S) A single authentication is required. Confidentiality impact (C:P) Partial confidentiality impact. Integrity impact (I:P) Partial integrity impact. Availability impact (A:P) Partial availability impact.	6.8	6.4	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

8.5

3.0

HIGH

CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H 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: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: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:H): Could take the service down hard or make it unusable for people who depend on it.

1.8

6.0

[email protected]

6.0

2.0

MEDIUM

AV:N/AC:M/Au:S/C:P/I:P/A:P 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:S): A single authentication is required.
Confidentiality impact (C:P): Partial confidentiality impact.
Integrity impact (I:P): Partial integrity impact.
Availability impact (A:P): Partial availability impact.

6.8

6.4

[email protected]

Affected software / configurations for CVE-2017-16857

Vendor	Product	Version	Raw CPE
atlassian	bitbucket_auto_unapprove_plugin	1.0.0	cpe:2.3:a:atlassian:bitbucket_auto_unapprove_plugin:1.0.0:::::::*
atlassian	bitbucket_auto_unapprove_plugin	1.0.0	cpe:2.3:a:atlassian:bitbucket_auto_unapprove_plugin:1.0.0:beta1::::::
atlassian	bitbucket_auto_unapprove_plugin	1.1.0	cpe:2.3:a:atlassian:bitbucket_auto_unapprove_plugin:1.1.0:::::::*
atlassian	bitbucket_auto_unapprove_plugin	1.2.0	cpe:2.3:a:atlassian:bitbucket_auto_unapprove_plugin:1.2.0:::::::*
atlassian	bitbucket_auto_unapprove_plugin	2.0.1	cpe:2.3:a:atlassian:bitbucket_auto_unapprove_plugin:2.0.1:::::::*
atlassian	bitbucket_auto_unapprove_plugin	2.0.2	cpe:2.3:a:atlassian:bitbucket_auto_unapprove_plugin:2.0.2:::::::*
atlassian	bitbucket_auto_unapprove_plugin	2.0.4	cpe:2.3:a:atlassian:bitbucket_auto_unapprove_plugin:2.0.4:::::::*
atlassian	bitbucket_auto_unapprove_plugin	2.1.1	cpe:2.3:a:atlassian:bitbucket_auto_unapprove_plugin:2.1.1:::::::*
atlassian	bitbucket_auto_unapprove_plugin	2.1.3	cpe:2.3:a:atlassian:bitbucket_auto_unapprove_plugin:2.1.3:::::::*
atlassian	bitbucket_auto_unapprove_plugin	2.2.0	cpe:2.3:a:atlassian:bitbucket_auto_unapprove_plugin:2.2.0:::::::*
atlassian	bitbucket_auto_unapprove_plugin	3.0.0	cpe:2.3:a:atlassian:bitbucket_auto_unapprove_plugin:3.0.0:::::::*

References for CVE-2017-16857

URL	Tags
https://jira.atlassian.com/browse/BSERV-10439	Issue Tracking Vendor Advisory

URL

CVE-2017-16857

Exploit prediction scoring system (EPSS) score for CVE-2017-16857

Common vulnerability scoring system (CVSS) metrics for CVE-2017-16857

Weakness enumeration for CVE-2017-16857

Affected software / configurations for CVE-2017-16857

References for CVE-2017-16857