CVE-2020-16171

Exp

An issue was discovered in Acronis Cyber Backup before 12.5 Build 16342. Some API endpoints on port 9877 under /api/ams/ accept an additional custom Shard header. The value of this header is afterwards used in a separate web request issued by the application itself. This can be abused to conduct SSRF attacks against otherwise unreachable Acronis services that are bound to localhost such as the NotificationService on 127.0.0.1:30572.

Published: 2020-09-21 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-16171 is rated High Exploit Risk (73.2/100): CVSS Medium severity, with high exploitation likelihood (EPSS 5.50%, 92th percentile). 2 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2020-16171

EDB-ID Source Kind Published Link
49113 exploit_db edb 2020-11-27 Exploit-DB ↗
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2020-16171

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-16 5.44% 5.50% +0.07%
2 2026-06-15 11.21% 5.44% -5.77%
3 2026-03-06 — 11.21% —

Full EPSS history (25 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-16171

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.5 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/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: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:L)
Some sensitive info could get out, but not a total data dump.
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.
 3.9 2.5 [email protected]
6.4 2.0 MEDIUM
AV:N/AC:L/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:L)
Exploitation conditions are straightforward and predictable.
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.
 10.0 4.9 [email protected]

Weakness enumeration for CVE-2020-16171

Affected software / configurations for CVE-2020-16171

Vendor Product Version Raw CPE
acronis cyber_backup <= 12.5 cpe:2.3:a:acronis:cyber_backup:*:*:*:*:*:*:*:*
acronis cyber_backup 12.5 cpe:2.3:a:acronis:cyber_backup:12.5:-:*:*:*:*:*:*
acronis cyber_backup 12.5 cpe:2.3:a:acronis:cyber_backup:12.5:10130:*:*:*:*:*:*
acronis cyber_backup 12.5 cpe:2.3:a:acronis:cyber_backup:12.5:10330:*:*:*:*:*:*
acronis cyber_backup 12.5 cpe:2.3:a:acronis:cyber_backup:12.5:11010:*:*:*:*:*:*
acronis cyber_backup 12.5 cpe:2.3:a:acronis:cyber_backup:12.5:13160:*:*:*:*:*:*
acronis cyber_backup 12.5 cpe:2.3:a:acronis:cyber_backup:12.5:13400:*:*:*:*:*:*
acronis cyber_backup 12.5 cpe:2.3:a:acronis:cyber_backup:12.5:14280:*:*:*:*:*:*
acronis cyber_backup 12.5 cpe:2.3:a:acronis:cyber_backup:12.5:14330:*:*:*:*:*:*
acronis cyber_backup 12.5 cpe:2.3:a:acronis:cyber_backup:12.5:16180:*:*:*:*:*:*
acronis cyber_backup 12.5 cpe:2.3:a:acronis:cyber_backup:12.5:16318:*:*:*:*:*:*
acronis cyber_backup 12.5 cpe:2.3:a:acronis:cyber_backup:12.5:16327:*:*:*:*:*:*
acronis cyber_backup 12.5 cpe:2.3:a:acronis:cyber_backup:12.5:7641:*:*:*:*:*:*
acronis cyber_backup 12.5 cpe:2.3:a:acronis:cyber_backup:12.5:7970:*:*:*:*:*:*
acronis cyber_backup 12.5 cpe:2.3:a:acronis:cyber_backup:12.5:8850:*:*:*:*:*:*
acronis cyber_backup 12.5 cpe:2.3:a:acronis:cyber_backup:12.5:9010:*:*:*:*:*:*

References for CVE-2020-16171

cvelogic Threat Intelligence