The (1) ssh2_load_userkey and (2) ssh2_save_userkey functions in PuTTY 0.51 through 0.63 do not properly wipe SSH-2 private keys from memory, which allows local users to obtain sensitive information by reading the memory.
Conclusion & alert: CVE-2015-2157 is rated Low Risk (17/100): CVSS Low severity, with low exploitation likelihood (EPSS 0.09%). Mandatory action: Low composite risk—no urgent action required; patch on your normal maintenance cycle and revisit priority if CVSS or EPSS increases.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
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 | 2026-03-01 | 0.27% | 0.09% | -0.18% |
| 2 | 2026-02-04 | 0.09% | 0.27% | +0.18% |
| 3 | 2026-02-01 | — | 0.09% | — |
Full EPSS history (30 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 2.1 | 2.0 | LOW |
|
3.9 | 2.9 | [email protected] |
| vendor | priority | summary | link |
|---|---|---|---|
debian
|
not yet assigned | CVE-2015-2157 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-2015-2157 |
ubuntu
|
low | CVE-2015-2157 low priority: Ubuntu including 1 source packages (putty), 10 status rows across 10 suites (lucid, precise, trusty, upstream, utopic, vivid, wily, xenial, yakkety, zesty): not-affected 5, released 3, ignored 2. | https://ubuntu.com/security/CVE-2015-2157 |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| debian | debian_linux | 7.0 | cpe:2.3:o:debian:debian_linux:7.0:*:*:*:*:*:*:* |
| fedoraproject | fedora | 20 | cpe:2.3:o:fedoraproject:fedora:20:*:*:*:*:*:*:* |
| fedoraproject | fedora | 22 | cpe:2.3:o:fedoraproject:fedora:22:*:*:*:*:*:*:* |
| opensuse | opensuse | 13.1 | cpe:2.3:o:opensuse:opensuse:13.1:*:*:*:*:*:*:* |
| opensuse | opensuse | 13.2 | cpe:2.3:o:opensuse:opensuse:13.2:*:*:*:*:*:*:* |
| putty | putty | 0.51 | cpe:2.3:a:putty:putty:0.51:*:*:*:*:*:*:* |
| putty | putty | 0.52 | cpe:2.3:a:putty:putty:0.52:*:*:*:*:*:*:* |
| putty | putty | 0.53b | cpe:2.3:a:putty:putty:0.53b:*:*:*:*:*:*:* |
| putty | putty | 0.54 | cpe:2.3:a:putty:putty:0.54:*:*:*:*:*:*:* |
| putty | putty | 0.55 | cpe:2.3:a:putty:putty:0.55:*:*:*:*:*:*:* |
| putty | putty | 0.56 | cpe:2.3:a:putty:putty:0.56:*:*:*:*:*:*:* |
| putty | putty | 0.57 | cpe:2.3:a:putty:putty:0.57:*:*:*:*:*:*:* |
| putty | putty | 0.58 | cpe:2.3:a:putty:putty:0.58:*:*:*:*:*:*:* |
| putty | putty | 0.59 | cpe:2.3:a:putty:putty:0.59:*:*:*:*:*:*:* |
| putty | putty | 0.60 | cpe:2.3:a:putty:putty:0.60:*:*:*:*:*:*:* |
| putty | putty | 0.61 | cpe:2.3:a:putty:putty:0.61:*:*:*:*:*:*:* |
| putty | putty | 0.62 | cpe:2.3:a:putty:putty:0.62:*:*:*:*:*:*:* |
| putty | putty | 0.63 | cpe:2.3:a:putty:putty:0.63:*:*:*:*:*:*:* |
| simon_tatham | putty | 0.53 | cpe:2.3:a:simon_tatham:putty:0.53:*:*:*:*:*:*:* |