How severe is CVE-2020-16171?

CVE-2020-16171 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2020-16171 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 6% (92nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-16171?

CVE-2020-16171 primarily affects Acronis Cyber Backup. In total, 16 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-16171?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2020-16171 published?

CVE-2020-16171 was published on 2020-09-21 and last updated on 2026-06-17.

CVE-2020-16171

CVE-2020-16171 is a medium-severity vulnerability in Acronis Cyber Backup with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-918.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
CVSS v2: 6.4
EPSS exploit prediction: 6% (92nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-918
Affected product: Acronis Cyber Backup
Published: 2020-09-21
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2020-16171?: 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.
How severe is CVE-2020-16171?: CVE-2020-16171 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2020-16171 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 6% (92nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-16171?: CVE-2020-16171 primarily affects Acronis Cyber Backup. In total, 16 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-16171?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2020-16171 published?: CVE-2020-16171 was published on 2020-09-21 and last updated on 2026-06-17.

References

Affected products (16)

cpe:2.3:a:acronis:cyber_backup:*:*:*:*:*:*:*:*
cpe:2.3:a:acronis:cyber_backup:12.5:-:*:*:*:*:*:*
cpe:2.3:a:acronis:cyber_backup:12.5:10130:*:*:*:*:*:*
cpe:2.3:a:acronis:cyber_backup:12.5:10330:*:*:*:*:*:*
cpe:2.3:a:acronis:cyber_backup:12.5:11010:*:*:*:*:*:*
cpe:2.3:a:acronis:cyber_backup:12.5:13160:*:*:*:*:*:*
cpe:2.3:a:acronis:cyber_backup:12.5:13400:*:*:*:*:*:*
cpe:2.3:a:acronis:cyber_backup:12.5:14280:*:*:*:*:*:*
cpe:2.3:a:acronis:cyber_backup:12.5:14330:*:*:*:*:*:*
cpe:2.3:a:acronis:cyber_backup:12.5:16180:*:*:*:*:*:*
cpe:2.3:a:acronis:cyber_backup:12.5:16318:*:*:*:*:*:*
cpe:2.3:a:acronis:cyber_backup:12.5:16327:*:*:*:*:*:*
cpe:2.3:a:acronis:cyber_backup:12.5:7641:*:*:*:*:*:*
cpe:2.3:a:acronis:cyber_backup:12.5:7970:*:*:*:*:*:*
cpe:2.3:a:acronis:cyber_backup:12.5:8850:*:*:*:*:*:*
cpe:2.3:a:acronis:cyber_backup:12.5:9010:*:*:*:*:*:*

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