CVE-2026-48852: putty Reachable Assertion
Vulnerability summary
CVE-2026-48852 is a low (CVSS 3.7) Reachable Assertion vulnerability in putty. EPSS estimates a 0.27% chance of exploitation in the next 30 days, higher than 19.9% of scored vulnerabilities.
Not severe (CVSS 3.7, network access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 2 · Related 2Timeline
- 25-05-2026PublishedVulnerability first disclosed.
- 26-05-2026Last modifiedVulnerability information updated.
Description
PuTTY 0.71 before 0.84 has an assertion failure in ECDSA signature verification.
CVSS metrics
4 scores · 4 sources · 1 version- OSV · UbuntuEcosystem advisory · calculated3.7LowCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
- OSV · DebianEcosystem advisory · calculated3.7LowCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
- NVDNIST3.7LowCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
EPSS trend
Probability
0.27%
Chance of exploitation in the next 30 days
Percentile
20%
Versus all other CVEs
30-day change
Decrease -0.08 pp
From 0.35% on 04-10-2026
Known exploited
Compare KEV catalogsNot in the CISA KEV catalog.
Not in the ENISA CNW catalog.
Not in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.
Debian1 product
- puttyAll versions (No fix recorded) | < 0.84-1
Putty1 product
- putty≥ 0.71, < 0.84
Ubuntu1 product
- puttyAll versions (No fix recorded)
3 vendors · 3 products
References
5 links- www.chiark.greenend.org.uk/~sgtatham/putty/wishlist/ecdsa-remotely-triggerable-assertion.htmlREPORTPatchVendor Advisory