CVE-2015-5309

Integer overflow in the terminal emulator in PuTTY before 0.66 allows remote attackers to cause a denial of service (memory corruption) or possibly execute arbitrary code via an ECH (erase characters) escape sequence with a large parameter value, which triggers a buffer underflow.

Published: 2015-12-07 Last update: 2026-05-06 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2015-5309 is rated Moderate Risk (45.4/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 1.74%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2015-5309

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-06-29 2.07% 1.74% -0.33%
2 2025-03-30 6.88% 2.07% -4.82%
3 2025-03-29 — 6.88% —

Full EPSS history (11 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2015-5309

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
4.3 2.0 MEDIUM
AV:N/AC:M/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 8.6 2.9 [email protected]

Weakness enumeration for CVE-2015-5309

OS Trackers for CVE-2015-5309

vendor priority summary link
debian not yet assigned CVE-2015-5309 not yet assigned priority: Debian including 1 source packages (putty), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2015-5309
gentoo normal CVE-2015-5309: 1 GLSA(s) (201606-01), 1 atom(s) (net-misc/putty); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2015-5309
ubuntu medium CVE-2015-5309 medium priority: Ubuntu including 1 source packages (putty), 12 status rows across 12 suites (artful, bionic, cosmic, disco, precise, trusty, upstream, vivid, wily, xenial, yakkety, zesty): not-affected 7, ignored 2, released 2, DNE 1. https://ubuntu.com/security/CVE-2015-5309

Affected software / configurations for CVE-2015-5309

Vendor Product Version Raw CPE
opensuse leap 42.1 cpe:2.3:o:opensuse:leap:42.1:*:*:*:*:*:*:*
opensuse opensuse 13.1 cpe:2.3:o:opensuse:opensuse:13.1:*:*:*:*:*:*:*
opensuse opensuse 13.2 cpe:2.3:o:opensuse:opensuse:13.2:*:*:*:*:*:*:*
simon_tatham putty <= 0.65 cpe:2.3:a:simon_tatham:putty:*:*:*:*:*:*:*:*

References for CVE-2015-5309

cvelogic Threat Intelligence