A vulnerability in the TLS protocol implementation of legacy Cisco ASA 5500 Series (ASA 5505, 5510, 5520, 5540, and 5550) devices could allow an unauthenticated, remote attacker to access sensitive information, aka a Return of Bleichenbacher's Oracle Threat (ROBOT) attack. An attacker could iteratively query a server running a vulnerable TLS stack implementation to perform cryptanalytic operations that may allow decryption of previously captured TLS sessions. Cisco Bug IDs: CSCvg97652.
CVE-2017-12373
MEDIUMNVD 5.95.9—Weaponized
EchelonGraph scoreMEDIUM confidence
Score 5.9 from GitHub Security Advisory published 2022-05-13. NVD baseline CVSS 5.9; sources differ by 0.0.
Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
5.9
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
- Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 13%CVSS: 5.9Exploit: NoneExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 5.9
- EG Score
- 5.9(medium)
- EPSS
- 95.8%
- KEV
- Not listed
Published
December 15, 2017
Last Modified
May 13, 2026
References (4)
- psirt@ciscohttp://www.securityfocus.com/bid/102170
- psirt@ciscohttps://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20171212-bleichenbacher
- af854a3a-2127-422b-91ae-364da2661108http://www.securityfocus.com/bid/102170
- af854a3a-2127-422b-91ae-364da2661108https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20171212-bleichenbacher
Frequently asked(5)
What is CVE-2017-12373?
CVE-2017-12373 is a medium vulnerability published on December 15, 2017. A vulnerability in the TLS protocol implementation of legacy Cisco ASA 5500 Series (ASA 5505, 5510, 5520, 5540, and 5550) devices could allow an unauthenticated, remote attacker to access sensitive information, aka a Return of Bleichenbacher's Oracle Threat (ROBOT) attack. An attacker could…
When was CVE-2017-12373 disclosed?
CVE-2017-12373 was first published in the National Vulnerability Database on December 15, 2017, with the most recent update on May 13, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2017-12373 actively exploited?
CVE-2017-12373 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 95.8% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2017-12373?
CVE-2017-12373 has a CVSS v3 base score of 5.9 (NVD).
How do I remediate CVE-2017-12373?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2017-12373, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
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