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Fencer Vulns
medium 5.9

CVE-2020-14002 json

PuTTY 0.68 through 0.73 has an Observable Discrepancy leading to an information leak in the algorithm negotiation.

published 2020-06-29 6 y ago modified 2026-06-17 4 mo ago also EUVD-2020-6169

cvss
5.9
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
3.1%
EPSS 3.1% chance of exploitation in 30 days, percentile 87%
public exploits
0
none known

Summary

PuTTY 0.68 through 0.73 has an Observable Discrepancy leading to an information leak in the algorithm negotiation. This allows man-in-the-middle attackers to target initial connection attempts (where no host key for the server has been cached by the client).

Patch / fix

  • putty Debian 14, Debian 13, Debian 12 0.74-1

debian advisories DEBIAN-CVE-2020-14002

  • putty Alpine 3.24, Alpine 3.23, Alpine 3.22 +13 more 0.74-r0

alpine advisories ALPINE-CVE-2020-14002

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2020-14002 updated cvss 4.3

putty: Observable Discrepancy leading to an information leak in the algorithm negotiation

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

3.13% chance of exploitation in the next 30 days, higher than 87% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:P/I:N/A:N

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.