CVE catalog

CVE-2026-4115

Severity: Medium · CVSS 6.3
Published: Mar 22, 2026, 12:15:07 PM UTC
Source: [NVD] · [CVE record]
EPSS: 0.55% · Oct 25, 2026

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.

Vulnerable and fixed packages

Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.

Distribution	Package	Release	Version	Status
Debian	putty	sid	`0.85-3`	fixed
Debian	putty	forky	`0.85-3`	fixed
Debian	putty	trixie	`0.83-3`	vulnerable
Debian	putty	bookworm	`0.78-2+deb12u2`	vulnerable
Debian	putty	bookworm-security	`0.78-2+deb12u1`	vulnerable
Cpe	putty	Not reported	Not reported	vulnerable

Fixed-version evidence

Distribution	Package	Type	Release	Fixed version	Urgency	Origin	Bugs
Debian	putty	source	sid	`0.84-1`	unimportant	Not reported	Not reported
Debian	putty	source	forky	`0.84-1`	unimportant	Not reported	Not reported
Debian	putty	source	trixie	`(unfixed)`	unimportant	Not reported	Not reported
Debian	putty	source	bookworm	`(unfixed)`	unimportant	Not reported	Not reported

OpenFactory catalog packages

[Debian 12 (Bookworm)]

[pterm]Affected
Source package: [putty]
Details (4)
- 0.78-2+deb12u2 · amd64 · bookworm
  Affected
  nvd · putty · debian · bookworm; nvd · putty · debian · 12
- 0.78-2+deb12u2 · arm64 · bookworm
  Affected
  nvd · putty · debian · bookworm; nvd · putty · debian · 12
- 0.78-2+deb12u1 · amd64 · bookworm-security
  Affected
  nvd · putty · debian · bookworm; nvd · putty · debian · 12
- 0.78-2+deb12u1 · arm64 · bookworm-security
  Affected
  nvd · putty · debian · bookworm; nvd · putty · debian · 12
[putty]Affected
Details (4)
- 0.78-2+deb12u2 · amd64 · bookworm
  Affected
  nvd · putty · debian · bookworm; nvd · putty · debian · 12
- 0.78-2+deb12u2 · arm64 · bookworm
  Affected
  nvd · putty · debian · bookworm; nvd · putty · debian · 12
- 0.78-2+deb12u1 · amd64 · bookworm-security
  Affected
  nvd · putty · debian · bookworm; nvd · putty · debian · 12
- 0.78-2+deb12u1 · arm64 · bookworm-security
  Affected
  nvd · putty · debian · bookworm; nvd · putty · debian · 12
[putty-doc]Affected
Source package: [putty]
Details (4)
- 0.78-2+deb12u2 · all · bookworm
  Affected
  nvd · putty · debian · bookworm; nvd · putty · debian · 12
- 0.78-2+deb12u2 · all · bookworm
  Affected
  nvd · putty · debian · bookworm; nvd · putty · debian · 12
- 0.78-2+deb12u1 · all · bookworm-security
  Affected
  nvd · putty · debian · bookworm; nvd · putty · debian · 12
- 0.78-2+deb12u1 · all · bookworm-security
  Affected
  nvd · putty · debian · bookworm; nvd · putty · debian · 12
[putty-tools]Affected
Source package: [putty]
Details (4)
- 0.78-2+deb12u2 · amd64 · bookworm
  Affected
  nvd · putty · debian · bookworm; nvd · putty · debian · 12
- 0.78-2+deb12u2 · arm64 · bookworm
  Affected
  nvd · putty · debian · bookworm; nvd · putty · debian · 12
- 0.78-2+deb12u1 · amd64 · bookworm-security
  Affected
  nvd · putty · debian · bookworm; nvd · putty · debian · 12
- 0.78-2+deb12u1 · arm64 · bookworm-security
  Affected
  nvd · putty · debian · bookworm; nvd · putty · debian · 12

[Debian 13 (Trixie)]

[pterm]Affected
Source package: [putty]
Details (2)
- 0.83-3 · amd64 · trixie
  Affected
  nvd · putty · debian · 13
- 0.83-3 · arm64 · trixie
  Affected
  nvd · putty · debian · 13
[putty]Affected
Details (2)
- 0.83-3 · amd64 · trixie
  Affected
  nvd · putty · debian · 13
- 0.83-3 · arm64 · trixie
  Affected
  nvd · putty · debian · 13
[putty-doc]Affected
Source package: [putty]
Details (2)
- 0.83-3 · all · trixie
  Affected
  nvd · putty · debian · 13
- 0.83-3 · all · trixie
  Affected
  nvd · putty · debian · 13
[putty-tools]Affected
Source package: [putty]
Details (2)
- 0.83-3 · amd64 · trixie
  Affected
  nvd · putty · debian · 13
- 0.83-3 · arm64 · trixie
  Affected
  nvd · putty · debian · 13

Observed: Oct 23, 2026, 10:39:43 PM UTC

References

[Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX]