How severe is CVE-2017-12373?

CVE-2017-12373 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2017-12373 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 13% (96th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2017-12373?

CVE-2017-12373 primarily affects Cisco Adaptive Security Appliance 5505 Firmware. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2017-12373?

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

When was CVE-2017-12373 published?

CVE-2017-12373 was published on 2017-12-15 and last updated on 2026-06-17.

CVE-2017-12373

CVE-2017-12373 is a medium-severity vulnerability in Cisco Adaptive Security Appliance 5505 Firmware with a CVSS 3.x base score of 5.9. Its EPSS exploit-prediction score of 13% places it in the 96th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-203.

Key facts

Severity: Medium (CVSS 3.x base score 5.9)
CVSS v2: 4.3
EPSS exploit prediction: 13% (96th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-203
Affected product: Cisco Adaptive Security Appliance 5505 Firmware
Published: 2017-12-15
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2017-12373?: 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.
How severe is CVE-2017-12373?: CVE-2017-12373 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2017-12373 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 13% (96th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2017-12373?: CVE-2017-12373 primarily affects Cisco Adaptive Security Appliance 5505 Firmware. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2017-12373?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2017-12373 published?: CVE-2017-12373 was published on 2017-12-15 and last updated on 2026-06-17.

References

Affected products (5)

cpe:2.3:o:cisco:adaptive_security_appliance_5505_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:cisco:adaptive_security_appliance_5510_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:cisco:adaptive_security_appliance_5520_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:cisco:adaptive_security_appliance_5540_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:cisco:adaptive_security_appliance_5550_firmware:-:*:*:*:*:*:*:*

More vulnerabilities in Cisco Adaptive Security Appliance 5505 Firmware

CVE-2017-17428 — Medium (CVSS 5.9): Cavium Nitrox SSL, Nitrox V SSL, and TurboSSL software development kits (SDKs) allow remote attackers to decrypt TLS…

All CVEs affecting Cisco Adaptive Security Appliance 5505 Firmware →

Other CWE-203 (Observable Discrepancy) vulnerabilities

CVE-2019-25337 — Critical (CVSS 9.8): OwnCloud 8.1.8 contains a username enumeration vulnerability that allows remote attackers to discover user accounts by…
CVE-2026-23519 — Critical (CVSS 9.8): RustCrypto CMOV provides conditional move CPU intrinsics which are guaranteed on major platforms to execute in…
CVE-2025-27667 — Critical (CVSS 9.8): Vasion Print (formerly PrinterLogic) before Virtual Appliance Host 22.0.843 Application 20.0.1923 allows Administrative…
CVE-2024-25714 — Critical (CVSS 9.8): In Rhonabwy through 1.1.13, HMAC signature verification uses a strcmp function that is vulnerable to side-channel…
CVE-2024-25191 — Critical (CVSS 9.8): php-jwt 1.0.0 uses strcmp (which is not constant time) to verify authentication, which makes it easier to bypass…
CVE-2024-25190 — Critical (CVSS 9.8): l8w8jwt 2.2.1 uses memcmp (which is not constant time) to verify authentication, which makes it easier to bypass…

Browse all CWE-203 (Observable Discrepancy) vulnerabilities →