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Vulnerabilities

Vulnerability · CVE-2026-4115

A vulnerability was detected in PuTTY 0.83.

Published Mar 22, 2026 · catalog updated Jun 17, 2026 · A vulnerability was detected

Check if you run it

No confirmed exploitation is on record for CVE-2026-4115. EPSS is 0.24%. Act only if a listed version of A vulnerability was detected is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (A vulnerability was detected).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Low2.9
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.24%
Remediation
Advisory link
Affected products
cpe putty/putty

A vulnerability was detected in PuTTY 0.83. Affected is the function eddsa_verify of the file crypto/ecc-ssh.c of the component Ed25519 Signature Handler. The manipulation results in improper verification of cryptographic signature. The attack may be performed from remote. The attack requires a high level of complexity. The exploitability is told to be difficult. The exploit is now public and may be used. The real existence of this vulnerability is still doubted at the moment. The patch is identified as af996b5ec27ab79bae3882071b9d6acf16044549. It is advisable to implement a patch to correct this issue. The vendor was contacted early, responded in a very professional manner and quickly released a patch for the affected product. However, at the moment there is no proof that this flaw might have any real-world impact.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe putty/putty0.83

How to fix CVE-2026-4115

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-4115. EPSS is 0.24%. Act only if a listed version of A vulnerability was detected is installed.

Which versions are affected?

Compare what you have installed with 0.83. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-345: Insufficient Verification of Data Authenticity; CWE-347: Improper Verification of Cryptographic Signature. EPSS 0.24%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Mar 22, 2026 · NIST NVD

    Detected

    A vulnerability was detected in PuTTY 0.83. Affected is the function eddsa_verify of the file crypto/ecc-ssh.c of the component Ed25519 Signature Handler. The manipulation results in improper verification of cryptographic signature. The attack may be performed from remote. The attack requires a high level of complexity. The exploitability is told to be difficult. The exploit is now public and may

  2. Jun 17, 2026 · NIST NVD

    Updated

    A vulnerability was detected in PuTTY 0.83. Affected is the function eddsa_verify of the file crypto/ecc-ssh.c of the component Ed25519 Signature Handler. The manipulation results in improper verification of cryptographic signature. The attack may be performed from remote. The attack requires a high level of complexity. The exploitability is told to be difficult. The exploit is now public and may

Sources

  • CVE.orgVulnerability recordCVE-2026-4115

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-4115

    30-day exploitation probability 0.2%

    first.org
  • NIST NVDVulnerability recordCVE-2026-4115

    A vulnerability was detected in PuTTY 0.83. Affected is the function eddsa_verify of the file crypto/ecc-ssh.c of the component Ed25519 Signature Handler. The manipulation results in improper verification of cryptographic signature. The attack may be performed from remote. The at

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.