What is CVE-2026-48852?

CVE-2026-48852 is a low-severity vulnerability in Putty, classified under Reachable Assertion. CVSS score: 3.7/10. Published 2026-05-25.

How severe is CVE-2026-48852?

Low severity. CVSS v3 base score is 3.7 out of 10.

Vulnerability in Putty

CVE-2026-48852

PuTTY 0.71 before 0.84 has an assertion failure in ECDSA signature verification.

Published 2026-05-25 · last modified 2026-07-24.

CVSS v3 metric

CVSS v3 base score 3.7 (Low). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L.

EPSS exploit prediction

EPSS: 0.004 (26.5th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 26th percentile — 26.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · newest: 0.004 · change: +0.001

Affected products

Putty — versions 0.71

Weakness classification (CWE)

CWE-617 — Reachable Assertion

References

lists.tartarus.org/pipermail/putty-announce/2026/000042.html (Release Notes)
www.chiark.greenend.org.uk/~sgtatham/putty/wishlist/ecdsa-remotely-triggerable-… (Patch, Vendor Advisory)

Frequently asked questions

What is CVE-2026-48852?: CVE-2026-48852 is a low-severity vulnerability in Putty, classified under Reachable Assertion. CVSS score: 3.7/10. Published 2026-05-25.
How severe is CVE-2026-48852?: Low severity. CVSS v3 base score is 3.7 out of 10.