How severe is CVE-2017-9855?

CVE-2017-9855 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2017-9855 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (73rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2017-9855?

CVE-2017-9855 primarily affects Sma Sunny Boy 3600 Firmware. In total, 39 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2017-9855?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2017-9855 published?

CVE-2017-9855 was published on 2017-08-05 and last updated on 2026-06-17.

CVE-2017-9855

CVE-2017-9855 is a critical-severity vulnerability in Sma Sunny Boy 3600 Firmware with a CVSS 3.x base score of 9.8. 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-863.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 2% (73rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-863
Affected product: Sma Sunny Boy 3600 Firmware
Published: 2017-08-05
Last modified: 2026-06-17

Description

An issue was discovered in SMA Solar Technology products. A secondary authentication system is available for Installers called the Grid Guard system. This system uses predictable codes, and a single Grid Guard code can be used on any SMA inverter. Any such code, when combined with the installer account, allows changing very sensitive parameters. NOTE: the vendor reports that Grid Guard is not an authentication feature; it is only a tracing feature. Also, only Sunny Boy TLST-21 and TL-21 and Sunny Tripower TL-10 and TL-30 could potentially be affected

Frequently asked questions

What is CVE-2017-9855?: An issue was discovered in SMA Solar Technology products. A secondary authentication system is available for Installers called the Grid Guard system. This system uses predictable codes, and a single Grid Guard code can be used on any SMA inverter. Any such code, when combined with the installer account, allows changing very sensitive parameters. NOTE: the vendor reports that Grid Guard is not an authentication feature; it is only a tracing feature. Also, only Sunny Boy TLST-21 and TL-21 and Sunny Tripower TL-10 and TL-30 could potentially be affected
How severe is CVE-2017-9855?: CVE-2017-9855 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2017-9855 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (73rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2017-9855?: CVE-2017-9855 primarily affects Sma Sunny Boy 3600 Firmware. In total, 39 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2017-9855?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2017-9855 published?: CVE-2017-9855 was published on 2017-08-05 and last updated on 2026-06-17.

References

Affected products (39)

cpe:2.3:o:sma:sunny_boy_3600_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:sma:sunny_boy_5000_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:sma:sunny_tripower_core1_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:sma:sunny_tripower_15000tl_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:sma:sunny_tripower_20000tl_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:sma:sunny_tripower_25000tl_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:sma:sunny_tripower_5000tl_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:sma:sunny_tripower_12000tl_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:sma:sunny_tripower_60_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:sma:sunny_boy_3000tl_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:sma:sunny_boy_3600tl_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:sma:sunny_boy_4000tl_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:sma:sunny_boy_5000tl_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:sma:sunny_boy_1.5_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:sma:sunny_boy_2.5_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:sma:sunny_boy_3.0_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:sma:sunny_boy_3.6_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:sma:sunny_boy_4.0_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:sma:sunny_boy_5.0_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:sma:sunny_central_2200_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:sma:sunny_central_1000cp_xt_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:sma:sunny_central_800cp_xt_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:sma:sunny_central_850cp_xt_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:sma:sunny_central_900cp_xt_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:sma:sunny_central_500cp_xt_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:sma:sunny_central_630cp_xt_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:sma:sunny_central_720cp_xt_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:sma:sunny_central_760cp_xt_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:sma:sunny_central_storage_500_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:sma:sunny_central_storage_630_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:sma:sunny_central_storage_720_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:sma:sunny_central_storage_760_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:sma:sunny_central_storage_800_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:sma:sunny_central_storage_850_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:sma:sunny_central_storage_900_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:sma:sunny_central_storage_1000_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:sma:sunny_central_storage_2200_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:sma:sunny_central_storage_2500-ev_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:sma:sunny_boy_storage_2.5_firmware:-:*:*:*:*:*:*:*

More vulnerabilities in Sma Sunny Boy 3600 Firmware

CVE-2017-9861 — Critical (CVSS 9.8): An issue was discovered in SMA Solar Technology products. The SIP implementation does not properly use authentication…
CVE-2017-9860 — Critical (CVSS 9.8): An issue was discovered in SMA Solar Technology products. An attacker can use Sunny Explorer or the SMAdata2+ network…
CVE-2017-9859 — Critical (CVSS 9.8): An issue was discovered in SMA Solar Technology products. The inverters make use of a weak hashing algorithm to encrypt…
CVE-2017-9854 — Critical (CVSS 9.8): An issue was discovered in SMA Solar Technology products. By sniffing for specific packets on the localhost, plaintext…
CVE-2017-9853 — Critical (CVSS 9.8): An issue was discovered in SMA Solar Technology products. All inverters have a very weak password policy for the user…
CVE-2017-9852 — Critical (CVSS 9.8): An Incorrect Password Management issue was discovered in SMA Solar Technology products. Default passwords exist that…

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