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NVD / CVE Program· CNA mitre

CVE-2026-48850: PuTTY 0.72 before 0.84 has a double free in RSA KEX.

MediumCVSS 5.9 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 23/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.32% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. Special conditions such as timing or configuration are required.
  • Fixed version: putty (Debian:14) 0.84-1; putty (openSUSE:Leap 16.0) 0.85-bp160.1.1; putty (openSUSE:Tumbleweed) 0.85-2.1.
  • Severity is disputed: the assigning authority (CNA) scores it 3.7, NVD 5.9.

Low priority for now. Upgrade to putty (Debian:14) 0.84-1; putty (openSUSE:Leap 16.0) 0.85-bp160.1.1; putty (openSUSE:Tumbleweed) 0.85-2.1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

Published
May 25, 2026
Updated
Jul 24, 2026
EPSS
0.3% · 25th percentile

Report tools

JSON

Action score

23

Monitor

Low priority for now.

CVSS
23 / 40 · 5.9 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.3%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
5.9
CNA · mitre
3.7
2.2 point gap

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-48850

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
puttyputty

Versions reported by the vendor

Affected version ranges reported by the assigning authority (mitre). Independent of NVD's CPE analysis and usually ahead of it.

  • PuTTY PuTTY

    • 0.72 and later · before 0.84affected

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • putty putty0.72 and later · before 0.84

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12puttyfrom 0—
Debian:14puttybefore 0.84-10.84-1
openSUSE:Leap 16.0puttybefore 0.85-bp160.1.10.85-bp160.1.1
openSUSE:Tumbleweedputtybefore 0.85-2.10.85-2.1

Same product

putty: all records

Other highest-scoring records for the same primary product.

  • CVE-2017-6542The ssh_agent_channel_data function in PuTTY before 0.68 allows remote attackers to have unspecified impact via a large length value in an…
    46Plan
  • CVE-2004-1008Integer signedness error in the ssh2_rdpkt function in PuTTY before 0.56 allows remote attackers to execute arbitrary code via a…
    42Plan
  • CVE-2019-9898Potential recycling of random numbers used in cryptography exists within PuTTY before 0.71.
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2024-31497Apr 15, 2024 · 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…
    25Monitor
  • ← EarlierCVE-2026-4115Mar 22, 2026 · PuTTY Ed25519 Signature ecc-ssh.c eddsa_verify signature verification
    11Monitor
  • Later →CVE-2026-48851May 25, 2026 · PuTTY 0.77 before 0.84 uses a copy of the PuTTY icon as a trust indication for TELNET data but the trust status is not cleared between…
    12Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
debian:putty0.84-1 · Debian:14Package registry (OSV)
opensuse:putty0.85-2.1 · openSUSE:TumbleweedPackage registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · variant or chain candidate · public bounty program.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-415 · Double Free

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

References

Show all references (1 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records