CVE-2020-13397Network attack vector

Client crash via uninitialized FIPS cipher pointer

Published May 22, 2020 · Updated Aug 4, 2024

NULL pointer dereference in FreeRDP before 2.1.1 allows remote attackers controlling an RDP server to crash clients through FIPS negotiation. A server-supplied ENCRYPTION_METHOD_FIPS value sends an NLA client into security_fips_decrypt before rdp->fips_decrypt is initialized, and winpr_Cipher_Update dereferences the resulting NULL pointer. Reachability requires the client to connect to a server that advertises FIPS while the client expects NLA; the bounded consequence is termination of the client process.

CVSS severity5.5
Medium
EPSS probability0.54%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in FreeRDP before 2.1.1 allows remote attackers controlling an RDP server to crash clients through FIPS negotiation. A server-supplied ENCRYPTION_METHOD_FIPS value sends an NLA client into security_fips_decrypt before rdp->fips_decrypt is initialized, and winpr_Cipher_Update dereferences the resulting NULL pointer. Reachability requires the client to connect to a server that advertises FIPS while the client expects NLA; the bounded consequence is termination of the client process.

The record

CVE
CVE-2020-13397
Published
May 22, 2020
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-125, CAPEC-540, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 22, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
2.1NIST NVDAV:L/AC:L/Au:N/C:P/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-125Out-of-bounds Read
CAPEC-540Overread Buffers
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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