Multiple heap-based buffer overflows in the modpow function in PuTTY before 0.55 allow…
Priority MEDIUM 40Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- — Not recorded in CVSS 2.0
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- Partial · Partial · Partial
- Fix status
- No fix listed
Attack profile from CVSS 2.0 · NVD. Fix status from CNA.
Summary
Multiple heap-based buffer overflows in the modpow function in PuTTY before 0.55 allow (1) remote attackers to execute arbitrary code via an SSH2 packet with a base argument that is larger than the mod argument, which causes the modpow function to write memory before the beginning of its buffer, and (2) remote malicious servers to cause a denial of service (client crash) and possibly execute arbitrary code via a large bignum during authentication.
Why it matters now
EPSS 0.04114 90th percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | — | all versions | — | No fix listed | CNA |
- — Vendor— Affected all versions Fixed in — No fix listed CNA
CPE configurations NVD · 8
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:putty:putty:0.48:*:*:*:*:*:*:* | 0.48 | Vulnerable | PuTTY |
| cpe:2.3:a:putty:putty:0.49:*:*:*:*:*:*:* | 0.49 | Vulnerable | PuTTY |
| cpe:2.3:a:putty:putty:0.50:*:*:*:*:*:*:* | 0.50 | Vulnerable | PuTTY |
| cpe:2.3:a:putty:putty:0.51:*:*:*:*:*:*:* | 0.51 | Vulnerable | PuTTY |
| cpe:2.3:a:putty:putty:0.52:*:*:*:*:*:*:* | 0.52 | Vulnerable | PuTTY |
| cpe:2.3:a:putty:putty:0.53:*:*:*:*:*:*:* | 0.53 | Vulnerable | PuTTY |
| cpe:2.3:a:putty:putty:0.53b:*:*:*:*:*:*:* | 0.53b | Vulnerable | PuTTY |
| cpe:2.3:a:putty:putty:0.54:*:*:*:*:*:*:* | 0.54 | Vulnerable | PuTTY |
- cpe:2.3:a:putty:putty:0.48:*:*:*:*:*:*:* Versions 0.48 Vulnerable ·PuTTY
- cpe:2.3:a:putty:putty:0.49:*:*:*:*:*:*:* Versions 0.49 Vulnerable ·PuTTY
- cpe:2.3:a:putty:putty:0.50:*:*:*:*:*:*:* Versions 0.50 Vulnerable ·PuTTY
- cpe:2.3:a:putty:putty:0.51:*:*:*:*:*:*:* Versions 0.51 Vulnerable ·PuTTY
- cpe:2.3:a:putty:putty:0.52:*:*:*:*:*:*:* Versions 0.52 Vulnerable ·PuTTY
- cpe:2.3:a:putty:putty:0.53:*:*:*:*:*:*:* Versions 0.53 Vulnerable ·PuTTY
- cpe:2.3:a:putty:putty:0.53b:*:*:*:*:*:*:* Versions 0.53b Vulnerable ·PuTTY
- cpe:2.3:a:putty:putty:0.54:*:*:*:*:*:*:* Versions 0.54 Vulnerable ·PuTTY
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2004-1440
- 2026-10-03 Alias added: GHSA-8hpx-pjhm-89hr
References
More Putty vulnerabilities
- TI-2002-01283 Multiple SSH2 servers and clients do not properly handle large packets or large fields… CVSS 2.0HIGH 10.0
- TI-2023-26623 The SSH transport protocol with certain OpenSSH extensions, found in OpenSSH before 9.6… CVSS 3.1MEDIUM 5.9
- TI-2017-04321 The ssh_agent_channel_data function in PuTTY before 0.68 allows remote attackers to have… CVSS 3.0CRITICAL 9.8
- TI-2026-03565 PuTTY Ed25519 Signature ecc-ssh.c eddsa_verify signature verification CVSS 4.0MEDIUM 6.3
- TI-2002-01281 Multiple SSH2 servers and clients do not properly handle packets or data elements with… CVSS 2.0HIGH 10.0
- TI-2004-00914 Integer signedness error in the ssh2_rdpkt function in PuTTY before 0.56 allows remote… CVSS 2.0HIGH 10.0
Sources
- CVE-2004-1440 · CVE Program
- CVE-2004-1440 · NVD
- FIRST EPSS
- GHSA-8hpx-pjhm-89hr · GitHub Advisory Database · CC BY 4.0
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