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Fencer Intel
critical 9.8

CVE-2017-6542 in the critical feed json

The ssh_agent_channel_data function in PuTTY before 0.68 allows remote attackers to have unspecified impact via a large length value in an…

published 2017-03-27 9 y ago modified 2026-06-17 4 mo ago also EUVD-2017-15598

cvss
9.8
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
21.8%
EPSS 21.8% chance of exploitation in 30 days, percentile 97%
public exploits
1
Exploit-DB

Summary

The ssh_agent_channel_data function in PuTTY before 0.68 allows remote attackers to have unspecified impact via a large length value in an agent protocol message and leveraging the ability to connect to the Unix-domain socket representing the forwarded agent connection, which trigger a buffer overflow.

Patch / fix

  • putty Debian 14, Debian 13, Debian 12 0.67-3

debian advisories DEBIAN-CVE-2017-6542

  • putty Ubuntu 16.04 LTS 0.67-3build0.16.04.1

ubuntu advisories UBUNTU-CVE-2017-6542

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • putty openSUSE Tumbleweed 0.76-1.2

opensuse advisories openSUSE-SU-2024:11201-1

  • putty Alpine 3.5, Alpine 3.4, Alpine 3.3 +1 more 0.68-r0

alpine advisories ALPINE-CVE-2017-6542

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-2017-6542 updated cvss 6.4

putty: Integer overflow in the ssh_agent_channel_data

  • 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

Timeline

  1. Published
  2. First public exploit (EDB-42137)

Exploit prediction

21.82% chance of exploitation in the next 30 days, higher than 97% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • EDB-42137 PuTTY < 0.68 - 'ssh_agent_channel_data' Integer Overflow Heap Corruption dos, 2017-06-07

CVSS scores

assigned by version score vector
NVD 3.0 9.8 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P

Classification

Weakness
  • CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer

References

Sources

Fencer Intel 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.