CVE-2020-1044 [Medium] | Input Validation Bypass in Sql Server Reporting Services

A security feature bypass vulnerability exists in SQL Server Reporting Services (SSRS) when the server improperly validates attachments uploaded to reports. An attacker who successfully exploited this vulnerability could upload file types that were disallowed by an administrator. To exploit the vulnerability, an authenticated attacker would need to send a specially crafted request to an affected SSRS server. The update addresses the vulnerability by modifying how SSRS validates attachment uploads.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	4.45%	1.91%	-2.54%
2	2025-11-08	3.32%	4.45%	+1.12%
3	2025-08-02	—	3.32%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-15

4.45%

1.91%

-2.54%

2025-11-08

3.32%

4.45%

+1.12%

2025-08-02

—

3.32%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
4.3	3.1	MEDIUM	`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/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:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:N) Doesn’t really leak secrets in a meaningful way. Integrity (I:L) Attackers could change some data, but it’s limited—not everything goes. Availability (A:N) Service keeps running; no real outage angle.	2.8	1.4	[email protected]
6.5	3.1	MEDIUM	`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/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: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:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:N) Doesn’t really leak secrets in a meaningful 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.	2.8	3.6	[email protected]
4.0	2.0	MEDIUM	`AV:N/AC:L/Au:S/C:N/I:P/A:N` Click to expand Access vector (AV:N) Can be exploited remotely over network reachability. Access complexity (AC:L) Exploitation conditions are straightforward and predictable. Authentication (AU:S) A single authentication is required. Confidentiality impact (C:N) No confidentiality impact. Integrity impact (I:P) Partial integrity impact. Availability impact (A:N) No availability impact.	8.0	2.9	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

4.3

3.1

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/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:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N): Doesn’t really leak secrets in a meaningful way.
Integrity (I:L): Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N): Service keeps running; no real outage angle.

2.8

1.4

[email protected]

6.5

3.1

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/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: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:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N): Doesn’t really leak secrets in a meaningful 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.

2.8

3.6

[email protected]

4.0

2.0

MEDIUM

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

Access vector (AV:N): Can be exploited remotely over network reachability.
Access complexity (AC:L): Exploitation conditions are straightforward and predictable.
Authentication (AU:S): A single authentication is required.
Confidentiality impact (C:N): No confidentiality impact.
Integrity impact (I:P): Partial integrity impact.
Availability impact (A:N): No availability impact.

8.0

2.9

[email protected]

Affected software / configurations for CVE-2020-1044

Vendor	Product	Version	Raw CPE
microsoft	sql_server_reporting_services	2017	cpe:2.3:a:microsoft:sql_server_reporting_services:2017:::::::*
microsoft	sql_server_reporting_services	2019	cpe:2.3:a:microsoft:sql_server_reporting_services:2019:::::::*

References for CVE-2020-1044

URL	Tags
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1044	Patch Vendor Advisory

URL

CVE-2020-1044 | SQL Server Reporting Services Security Feature Bypass Vulnerability

Exploit prediction scoring system (EPSS) score for CVE-2020-1044

Common vulnerability scoring system (CVSS) metrics for CVE-2020-1044

Weakness enumeration for CVE-2020-1044

Affected software / configurations for CVE-2020-1044

References for CVE-2020-1044