What is CVE-2017-6542?

CVE-2017-6542 is a critical-severity vulnerability in openSUSE Project Leap, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 9.8/10. Published 2017-03-27.

How severe is CVE-2017-6542?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Is CVE-2017-6542 known to be exploited?

2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Buffer overflow in openSUSE Project Leap

CVE-2017-6542

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.

Vulnerability class: Buffer Overflow

Published 2017-03-27 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.218 (97.6th percentile), scored 2026-10-24.

Moderate probability of exploitation in the next 30 days — watch for active exploitation reports. 98th percentile — 97.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.218 · newest: 0.218 · change: 0.000

Affected products

openSUSE Project Leap — versions 42.1
Putty
openSUSE Leap — versions 42.2

Weakness classification (CWE)

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

Public proof-of-concept exploits

References

www.securityfocus.com/bid/97156 (VDB Entry, Third Party Advisory, vdb-entry)
www.exploit-db.com/exploits/42137/ (exploit)
security.gentoo.org/glsa/201703-03 (vendor-advisory, VDB Entry, Third Party Advisory)
git.tartarus.org/
www.securitytracker.com/id/1038067 (vdb-entry)
www.chiark.greenend.org.uk/~sgtatham/putty/wishlist/vuln-agent-fwd-overflow.html (Patch, Vendor Advisory)
lists.opensuse.org/opensuse-updates/2017-03/msg00055.html (vendor-advisory, Third Party Advisory)
security.gentoo.org/glsa/201706-09 (vendor-advisory)

Frequently asked questions

What is CVE-2017-6542?: CVE-2017-6542 is a critical-severity vulnerability in openSUSE Project Leap, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 9.8/10. Published 2017-03-27.
How severe is CVE-2017-6542?: Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2017-6542 known to be exploited?: 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.