CVSS Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
Lifecycle Timeline
5Description
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 弱身份验证. 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.
Analysis
PuTTY versions up to 0.83 contain a weak authentication vulnerability in the Ed25519 signature verification function (eddsa_verify in crypto/ecc-ssh.c) that allows remote attackers to potentially forge or manipulate digital signatures due to improper validation of Ed25519 signature components. While a public proof-of-concept exploit exists and the vulnerability affects signature verification, the real-world impact remains unproven, with CVSS 3.7 (low severity) and EPSS probability indicating exploitation is difficult and requires high complexity. …
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Remediation
During next maintenance window: Apply vendor patches when convenient. Vendor patch is available.
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Priority Score
Vendor Status
Debian
| Release | Status | Fixed Version | Urgency |
|---|---|---|---|
| bullseye | vulnerable | 0.74-1+deb11u2 | - |
| bullseye (security) | vulnerable | 0.74-1+deb11u1 | - |
| bookworm | vulnerable | 0.78-2+deb12u2 | - |
| bookworm (security) | vulnerable | 0.78-2+deb12u1 | - |
| forky, sid, trixie | vulnerable | 0.83-3 | - |
| (unstable) | fixed | (unfixed) | unimportant |
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External POC / Exploit Code
Leaving vuln.today
EUVD-2026-14301
GHSA-p96h-94q2-fh5v