CVE-2017-6542Putty Memory Corruption
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…
Published Mar 27, 2017 · Updated Aug 4, 2026 · Also known as ALPINE-CVE-2017-6542, DEBIAN-CVE-2017-6542, UBUNTU-CVE-2017-6542
Key Facts
Patch immediately- CVE-2017-6542 is a critical-severity vulnerability (CVSS 9.8 v3.1) affecting Putty, Leap (Opensuse).
- It is not listed in any known-exploited vulnerabilities catalog. Public exploit code is available.
- EPSS estimates a 22% probability of exploitation in the next 30 days.
- Fixed versions are available, including Putty 0.67-3, Putty 0.67-3build0.16.04.1, Putty 0.68-12.1.
- Brandefense priority: patch immediately, because public exploit code exists for a high-severity flaw.
Scores
CVSS v3.1
9.8
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
22%
Higher than 97.6% of all scored CVEs
Exploit maturity
Proof of concept
ATLAS score
43/100
Publication score, see How it works
Exploitation Verdict
KEV listed
Not listed
Federal due date
None
No federal due date
Ransomware use
Not reported
Attributed actors
None named
Exploit & Defence Guidance
Exploit maturity
Proof of concept
Public exploit code
1
Proof-of-concept links
In-the-wild evidence
0
Reports of active use
Advisories And Exploit References
- advisoryhttps://security.alpinelinux.org/vuln/CVE-2017-6542
- advisoryhttps://security-tracker.debian.org/tracker/CVE-2017-6542
- advisoryhttps://ubuntu.com/security/CVE-2017-6542
- advisoryhttps://www.cve.org/CVERecord?id=CVE-2017-6542
- advisoryopenSUSE-SU-2017:0741
- advisoryhttps://git.tartarus.org/?p=simon/putty.git;a=commitdiff;h=4ff22863d895cb7ebfced4cf923a012a614adaa8
Description
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.
Affected Products
23 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| PuttyPutty | See advisory | 0.67 |
| LeapOpensuse | 42.2, 42.1 | n/a |
Patched Releases
Putty
0.67-3, 0.67-3build0.16.04.1, 0.68-12.1, 0.68-r0, 0.76-1.2, 0.67
Timeline
Publicly disclosed
Mar 27, 2017
Last updated
Aug 4, 2026
Weakness Type
- CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer
References
- advisorysecurity.alpinelinux.org · CVE-2017-6542
- advisorysecurity-tracker.debian.org · CVE-2017-6542
- advisoryubuntu.com · CVE-2017-6542
- advisorycve.org · CVERecord
- advisoryopenSUSE-SU-2017:0741
FAQ
Common Questions.
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.
Affected: Putty; Leap (Opensuse) versions 42.2, 42.1. The full list is in the CVE brief.
It is not listed in any known-exploited vulnerabilities catalog.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
Public exploit code is available.
Fixed versions are available, including Putty 0.67-3, Putty 0.67-3build0.16.04.1, Putty 0.68-12.1.
Brandefense priority: patch immediately, because public exploit code exists for a high-severity flaw.
Is CVE-2017-6542 On Your Attack Surface?
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