Free and open · new CVEs checked every 20 minutesStatusRSSOpen dataContact

CVE-2021-39139: XStream is a simple library to serialize objects to XML and back again

58
This month
HIGH 8.5WATCHLISTUPGRADEMITIGATEMITIGATE

CVE-2021-39139 is a high-severity flaw (CVSS 8.5) affecting xstream, debian linux, fedora. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

XStream is a simple library to serialize objects to XML and back again. In affected versions this vulnerability may allow a remote attacker to load and execute arbitrary code from a remote host only by manipulating the processed input stream. A user is only affected if using the version out of the box with JDK 1.7u21 or below. However, this scenario can be adjusted easily to an external Xalan that works regardless of the version of the Java runti

Why this priority

  • High severity
  • EPSS top 8%: very likely to be exploited
  • On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score8.5 (High)
Attack vectorNetwork (remote)
Attack complexityHigh
Privileges neededLow
User interactionNone
EPSS exploit chance4.5% (top 8%)
CISA exploited listNo
WeaknessCWE-434, CWE-502
Published2021-08-23
Last modified2026-10-07
Publisher (CNA): GitHub, Inc. · Vendor: debian · fedoraproject · netapp · oracle · xstream

Share: LinkedIn · X · Reddit

Last updated 2026-10-07 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

xstream xstream UPGRADE
Affected: < 1.4.18
Fixed in: 1.4.18
Safe to downgrade to: no unaffected older release
1. Check installed version
apt-cache policy xstream || rpm -q xstream || xstream --version
2. UPGRADE to 1.4.18 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade xstream
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade xstream
Note
Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.
debian debian linux MITIGATE
Affected: 9.0 · 10.0 · 11.0
Fixed in: no fixed release known
Safe to downgrade to: a release before 9.0
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
fedoraproject fedora MITIGATE
Affected: 33 · 34 · 35
Fixed in: no fixed release known
Safe to downgrade to: a release before 33
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
netapp snapmanager MITIGATE
Affected: all versions
Fixed in: no fixed release known
Safe to downgrade to: no unaffected older release
1. Check installed version
apt-cache policy snapmanager || rpm -q snapmanager || snapmanager --version
No fixed or unaffected release known
Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.
netapp snapmanager MITIGATE
Affected: all versions
Fixed in: no fixed release known
Safe to downgrade to: no unaffected older release
1. Check installed version
apt-cache policy snapmanager || rpm -q snapmanager || snapmanager --version
No fixed or unaffected release known
Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.
oracle business activity monitoring DOWNGRADE
Affected: 12.2.1.4.0
Fixed in: no fixed release known
Safe to downgrade to: a release before 12.2.1.4.0
1. Check installed version
apt-cache policy business-activity-monitoring || rpm -q business-activity-monitoring || business-activity-monitoring --version
2. No fixed release: DOWNGRADE to a release before 12.2.1.4.0 (Debian / Ubuntu)
apt-cache madison business-activity-monitoring sudo apt install business-activity-monitoring=<VERSION_BEFORE_12.2.1.4.0> sudo apt-mark hold business-activity-monitoring
2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list business-activity-monitoring sudo dnf downgrade business-activity-monitoring-<VERSION_BEFORE_12.2.1.4.0> sudo dnf versionlock add business-activity-monitoring
Downgrade risk
Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.
After downgrade
Restart the service, and keep the package held until a fixed release ships.
Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-39139?

xstream: upgrade to 1.4.18; debian linux: mitigate or apply the listed mitigation; fedora: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-39139 being exploited?

CVE-2021-39139 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-39139 affect?

CVE-2021-39139 affects xstream, debian linux, fedora. Severity is high (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 to load and execute arbitrary code from a remote host only by manipulating the processed input strea

How urgent is CVE-2021-39139?

Priority 58/100. High severity; EPSS top 8%: very likely to be exploited; On your watchlist

Software pages

Java vulnerabilities · Debian vulnerabilities

Related CVEs

References

← Back to latest CVEs

Get the weekly exploited-CVE digest by emailThe CVEs being attacked this week and how to fix them. No spam, unsubscribe any time.