CVE-2024-31497

What it is

In PuTTY 0.68 through 0.80 before 0.81, biased ECDSA nonce generation allows an attacker to recover a user's NIST P-521 secret key via a quick attack in approximately 60 signatures. This is especially important in a scenario where an adversary is able to read messages signed by PuTTY or Pageant. The required set of signed messages may be publicly readable because they are stored in a public Git service that supports use of SSH for commit signing, and the signatures were made by Pageant through an agent-forwarding mechanism. In other words, an adversary may already have enough signature information to compromise a victim's private key, even if there is no further use of vulnerable PuTTY versions. After a key compromise, an adversary may be able to conduct supply-chain attacks on software maintained in Git. A second, independent scenario is that the adversary is an operator of an SSH server to which the victim authenticates (for remote login or file copy), even though this server is not fully trusted by the victim, and the victim uses the same private key for SSH connections to other services operated by other entities. Here, the rogue server operator (who would otherwise have no way to determine the victim's private key) can derive the victim's private key, and then use it for unauthorized access to those other services. If the other services include Git services, then again it may be possible to conduct supply-chain attacks on software maintained in Git. This also affects, for example, FileZilla before 3.67.0, WinSCP before 6.3.3, TortoiseGit before 2.15.0.1, and TortoiseSVN through 1.14.6.

At a glance

Exploitability

Can be exploited over the network without logging in. High risk of data exposure.

Exploit odds

5.7% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2024-04-15 20:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 07:28 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 5.7% in the next 30 days (EPSS).
• Severity: 5.9 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2024-04-15 20:15 UTC

Last modified

2026-06-17 07:28 UTC

Exploit probability

5.7% · EPSS, next 30 days

Weakness

CWE-338

Record status

Modified

Affected

• Putty < 0.81
• filezilla-project Filezilla Client < 3.67.0
• Winscp < 6.3.3
• Tortoisegit < 2.15.0.1
• Tigris Tortoisesvn < 1.14.6
• Fedoraproject Fedora 38
• Fedoraproject Fedora 39
• Fedoraproject Fedora 40

Attack profile CVSS 3.1 · 5.9

Attack vector

Network

Complexity

High

Privileges needed

None

User interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

None

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2024-31497.md and follow it. Check whether this project is affected by CVE-2024-31497. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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