CVE-2019-13163Network attack vector

Session-data disclosure via TLS CBC padding oracle

Published Feb 7, 2020 · Updated Aug 4, 2024

A TLS padding oracle in affected Fujitsu Interstage and Systemwalker products allows man-in-the-middle attackers to read protected session data. The Fujitsu TLS library distinguishes valid CBC padding from invalid padding even when the record MAC is wrong, exposing a plaintext oracle. Exploitation requires interception and modification of CBC-protected TLS traffic plus repeated victim requests; the reported consequence is confidentiality loss, not modification or service interruption.

CVSS severity5.9
Medium
EPSS probability0.60%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A TLS padding oracle in affected Fujitsu Interstage and Systemwalker products allows man-in-the-middle attackers to read protected session data. The Fujitsu TLS library distinguishes valid CBC padding from invalid padding even when the record MAC is wrong, exposing a plaintext oracle. Exploitation requires interception and modification of CBC-protected TLS traffic plus repeated victim requests; the reported consequence is confidentiality loss, not modification or service interruption.

The record

CVE
CVE-2019-13163
Published
Feb 7, 2020
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-326, T1557
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 7, 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

5.9NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
4.3NIST NVDAV:N/AC:M/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.

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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-326Inadequate Encryption Strength
T1557Adversary-in-the-Middle

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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