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Weekly Signal
Live intelligence Updated 19 Aug 2026 · 20:27 UTC

Debian, Fedoraproject, Netapp +2 more · Debian Linux, Fedora, Snapmanager +12 more

CVE-2021-39144

XStream Remote Code Execution Vulnerability

Recommended action

Validate affected assets and exposure now, then remediate on an accelerated schedule. Oracle Security patch Cpuapr2022

View response plan
CVSS8.5
EPSS98.1%
KEVYes
ExploitationConfirmed exploitation
RemediationExplicit patch identified ↓

Assessment

Why it matters

CISA lists this vulnerability as known to be exploited; exploitation is confirmed; EPSS is 98.1%; technical severity is CVSS 8.5.

XStream is a simple library to serialize objects to XML and back again. In affected versions this vulnerability may allow a remote attacker has sufficient rights to execute commands of the host only by manipulating the processed input stream. No user is affected, who followed the recommendation to setup XStream's security framework with a whitelist limited to the minimal required types. XStream 1.4.18 uses no longer a blacklist by default, since it cannot be secured for general purpose.

Who should care

  • Teams operating Debian Linux, Fedora, Snapmanager +12 more
  • Vulnerability and exposure management teams
  • Security operations teams monitoring exploitation activity

Response plan

What I would do

  1. Confirm whether Debian Linux, Fedora, Snapmanager +12 more is present in the environment.
  2. Identify affected versions and establish whether vulnerable services are exposed or reachable.
  3. Oracle Security patch Cpuapr2022
  4. Review relevant security telemetry for evidence of attempted or successful exploitation.
  5. Document the remediation decision and track it to verified completion.

Treatment intelligence

Remediation intelligence

Not yet verified

Vendor sources are listed before government and third-party guidance. Confirm product applicability and change prerequisites before deployment.

Verification noteAutomated link verification has not completed for this guidance yet.

Patch

Upgrade

Advisory

Required Action

Technical details

CVSS vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
CWE
CWE-94
Affected versions
Debian Debian Linux (Version 9.0 | Version 10.0 | Version 11.0); Fedoraproject Fedora (Version 33 | Version 34 | Version 35); Netapp Snapmanager (Version - | Version -); Oracle Business Activity Monitoring (Version 12.2.1.4.0); Oracle Commerce Guided Search (Version 11.3.2); Oracle Communications Billing And Revenue Management Elastic Charging Engine (Version 11.3 | Version 12.0); Oracle Communications Cloud Native Core Automated Test Suite (Version 1.9.0); Oracle Communications Cloud Native Core Binding Support Function (Version 1.10.0)
Fixed versions
Xstream Xstream (Fixed from 1.4.18)
Published
23 August 2021
Attack vector
Network
Privileges required
Low
User interaction
None

Signal timeline

  1. CVE published
  2. Added to CISA KEV
  3. Latest EPSS score: 98.1%
  4. Signal calculated at 83

External references

Live public intelligence This assessment combines public-source evidence. Validate the affected product, version and exposure against your own environment before making a risk decision.