How severe is CVE-2019-9898?

CVE-2019-9898 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-2019-9898 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (89th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2019-9898?

CVE-2019-9898 primarily affects Putty. In total, 7 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2019-9898?

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-2019-9898 published?

CVE-2019-9898 was published on 2019-03-21 and last updated on 2026-06-17.

CVE-2019-9898

CVE-2019-9898 is a critical-severity vulnerability in Putty 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-330.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 4% (89th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-330
Affected product: Putty
Published: 2019-03-21
Last modified: 2026-06-17

Description

Potential recycling of random numbers used in cryptography exists within PuTTY before 0.71.

Frequently asked questions

What is CVE-2019-9898?: Potential recycling of random numbers used in cryptography exists within PuTTY before 0.71.
How severe is CVE-2019-9898?: CVE-2019-9898 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-2019-9898 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (89th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2019-9898?: CVE-2019-9898 primarily affects Putty. In total, 7 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2019-9898?: 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-2019-9898 published?: CVE-2019-9898 was published on 2019-03-21 and last updated on 2026-06-17.

References

Affected products (7)

cpe:2.3:a:putty:putty:*:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:28:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:29:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
cpe:2.3:o:opensuse:leap:15.0:*:*:*:*:*:*:*
cpe:2.3:a:netapp:oncommand_unified_manager:-:*:*:*:*:*:*:*

More vulnerabilities in Putty

CVE-2004-1008 — Critical (CVSS 10.0): Integer signedness error in the ssh2_rdpkt function in PuTTY before 0.56 allows remote attackers to execute arbitrary…
CVE-2002-1358 — Critical (CVSS 10.0): Multiple SSH2 servers and clients do not properly handle lists with empty elements or strings, which may allow remote…
CVE-2002-1357 — Critical (CVSS 10.0): Multiple SSH2 servers and clients do not properly handle packets or data elements with incorrect length specifiers,…
CVE-2002-1359 — Critical (CVSS 10.0): Multiple SSH2 servers and clients do not properly handle large packets or large fields, which may allow remote…
CVE-2002-1360 — Critical (CVSS 10.0): Multiple SSH2 servers and clients do not properly handle strings with null characters in them when the string length is…
CVE-2019-17067 — Critical (CVSS 9.8): PuTTY before 0.73 on Windows improperly opens port-forwarding listening sockets, which allows attackers to listen on…

All CVEs affecting Putty →

Other CWE-330 (Use of Insufficiently Random Values) vulnerabilities

CVE-2023-22601 — Critical (CVSS 10.0): InHand Networks InRouter 302, prior to version IR302 V3.5.56, and InRouter 615, prior to version…
CVE-2026-25072 — Critical (CVSS 9.8): XikeStor SKS8310-8X Network Switch firmware versions 1.04.B07 and prior contain a predictable session identifier…
CVE-2026-27755 — Critical (CVSS 9.8): SODOLA SL902-SWTGW124AS firmware versions through 200.1.20 contain a weak session identifier generation vulnerability…
CVE-2026-27637 — Critical (CVSS 9.8): FreeScout is a free help desk and shared inbox built with PHP's Laravel framework. Prior to version 1.8.206,…
CVE-2025-64097 — Critical (CVSS 9.8): NervesHub is a web service that allows users to manage over-the-air (OTA) firmware updates of devices in the field. A…
CVE-2025-4607 — Critical (CVSS 9.8): The PSW Front-end Login & Registration plugin for WordPress is vulnerable to Privilege Escalation in all versions up…

Browse all CWE-330 (Use of Insufficiently Random Values) vulnerabilities →