PuTTY 0.83 Ed25519 Signature crypto/ecc-ssh.c eddsa_verify signature verification ⚔ [Disputed]

CVSS Meta Temp Score
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CTI Interest Score
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3.5$0-$5k0.64

Summaryinfo

A vulnerability was found in PuTTY 0.83. It has been rated as problematic. Affected by this vulnerability is the function eddsa_verify of the file crypto/ecc-ssh.c of the component Ed25519 Signature Handler. This manipulation causes signature verification. The identification of this vulnerability is CVE-2026-4115. It is possible to initiate the attack remotely. Furthermore, there is an exploit available. It is still unclear if this vulnerability genuinely exists. Applying a patch is the recommended action to fix 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.

Detailsinfo

A vulnerability was found in PuTTY 0.83. It has been declared as problematic. Affected by this vulnerability is the function eddsa_verify of the file crypto/ecc-ssh.c of the component Ed25519 Signature Handler. The manipulation with an unknown input leads to a signature verification vulnerability. The CWE definition for the vulnerability is CWE-347. The product does not verify, or incorrectly verifies, the cryptographic signature for data. As an impact it is known to affect integrity.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-4115. The exploitation appears to be difficult. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details and also a public exploit are known.

It is possible to download the exploit at github.com. It is declared as proof-of-concept. The real existence of this vulnerability is still doubted at the moment. 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. The vulnerability scanner Nessus provides a plugin with the ID 303305 (Linux Distros Unpatched Vulnerability : CVE-2026-4115), which helps to determine the existence of the flaw in a target environment.

Applying the patch af996b5ec27ab79bae3882071b9d6acf16044549 is able to eliminate this problem. The bugfix is ready for download at git.tartarus.org.

The vulnerability is also documented in the databases at CNNVD (CNNVD-202603-4155), Tenable (303305) and EUVD (EUVD-2026-14301). Additional details are provided at rfc-editor.org. If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Type

Name

Version

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 3.7
VulDB Meta Temp Score: 3.5

VulDB Base Score: 3.7
VulDB Temp Score: 3.4
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 3.7
CNA Vector: 🔒

CVSSv2info

AVACAuCIA
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Signature verification
CWE: CWE-347 / CWE-345
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Access: Public
Status: Proof-of-Concept
Programming Language: 🔒
Download: 🔒

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 303305
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2026-4115

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Patch
Status: 🔍

0-Day Time: 🔒

Patch: af996b5ec27ab79bae3882071b9d6acf16044549

Timelineinfo

03/22/2026 Advisory disclosed
03/22/2026 +0 days VulDB entry created
05/05/2026 +44 days VulDB entry last update

Sourcesinfo

Advisory: github.com
Status: Confirmed
Confirmation: 🔒
Disputed: 🔍

CVE: CVE-2026-4115 (🔒)
GCVE (CVE): GCVE-0-2026-4115
GCVE (VulDB): GCVE-100-352429
EUVD: 🔒
CNNVD: CNNVD-202603-4155 - PuTTY 数据伪造问题漏洞

scip Labs: https://www.scip.ch/en/?labs.20161013
Misc.: 🔒

Entryinfo

Created: 03/22/2026 12:53
Updated: 05/05/2026 21:10
Changes: 03/22/2026 12:53 (63), 03/22/2026 12:54 (1), 03/22/2026 15:36 (1), 03/23/2026 05:12 (2), 03/23/2026 17:29 (6), 05/05/2026 21:10 (33)
Complete: 🔍
Submitter: pythok
Cache ID: 216::103

Submitinfo

Accepted

  • Submit #775576: PuTTY Project (Simon Tatham) PuTTY 0.83 Improper Verification of Cryptographic Signature (by pythok)

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