CVE-2020-26217 — Remote Code Execution in XStream

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

• Documented patch — github.com (NIST National Vulnerability Database)
• Documented mitigation — github.com (NIST National Vulnerability Database)
• Documented patch — www.oracle.com (NIST National Vulnerability Database)
• Documented patch — www.oracle.com (NIST National Vulnerability Database)
• Documented patch — www.oracle.com (NIST National Vulnerability Database)
• Documented mitigation — x-stream.github.io (NIST National Vulnerability Database)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

1. Identify exposed assets running the affected vendor/product/version combinations (Apache Software Foundation Apache ActiveMQ, Debian Debian Linux, Netapp Snapmanager…).
2. Apply the fixed version or the patch documented under Remediation.
3. EPSS ahead of 100% of scored CVEs: prioritize it in the patch queue.
4. Search available logs for exploit probes matching the vulnerability class (injection), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-78 · OS Command Injection

Other CVEs with this weakness →

Public exploits, PoCs and detection templates

Public code that demonstrates or tests the flaw raises the odds of mass exploitation — and Nuclei templates help find vulnerable assets in your environment.

Warning: public PoCs are sometimes disguised malware. Use them only for authorized testing in an isolated environment. This portal does not host exploit code — it only points to the sources.

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 85.00%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

• Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
• Look for parameters with command/query metacharacters and unexpected child processes of the service.

Timeline

What happened to this CVE, newest first.

• 2026
• Affected products added · x-stream/xstream
  Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
• SSVC assessment updated
  Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
• Record published
  Oct 13, 2026
• Fix documented
  Oct 13, 2026 · NIST National Vulnerability Database
• CVSS changed · 8.8
  Oct 13, 2026 · NIST National Vulnerability Database
• Source status changed · → Analyzed
  Oct 13, 2026 · NIST National Vulnerability Database
• Record created in this database
  Oct 13, 2026 · NIST National Vulnerability Database
• 2020
• CVE published
  Nov 16, 2020 · GitHub_M

Source activity

Repeated readings are counted rather than listed.

• 1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

15 on the record

• x-stream.github.io/CVE-2020-26217.html
  Exploit, Mitigation, Vendor Advisory, x_refsource_CONFIRM, NIST National Vulnerability Database
• www.oracle.com//security-alerts/cpujul2021.html
  Patch, Third Party Advisory, x_refsource_MISC, NIST National Vulnerability Database
• github.com/x-stream/xstream/commit/0fec095d534126931c99fd38e9c6d41f5c685c1a
  Patch, Third Party Advisory, x_refsource_CONFIRM, NIST National Vulnerability Database
• www.oracle.com/security-alerts/cpuApr2021.html
  Patch, Third Party Advisory, x_refsource_MISC, NIST National Vulnerability Database
• www.oracle.com/security-alerts/cpuoct2021.html
  Patch, Third Party Advisory, x_refsource_MISC, NIST National Vulnerability Database
• github.com/x-stream/xstream/security/advisories/GHSA-mw36-7c6c-q4q2
  Mitigation, Third Party Advisory, x_refsource_CONFIRM, NIST National Vulnerability Database
• lists.apache.org/thread.html/r7c9fc255edc0b9cd9567093d131f6d33fde4c662aaf912460ef630e9
  Issue Tracking, Mailing List, mailing-list, x_refsource_MLIST, NIST National Vulnerability Database
• lists.apache.org/thread.html/r826a006fda71cc96fc87b6eca4b5d195f19a292ad36cea501682c38c
  Issue Tracking, Mailing List, mailing-list, x_refsource_MLIST, NIST National Vulnerability Database
• security.netapp.com/advisory/ntap-20210409-0004/
  Third Party Advisory, x_refsource_CONFIRM, NIST National Vulnerability Database
• lists.apache.org/thread.html/r2de526726e7f4db4a7cb91b7355070779f51a84fd985c6529c2f4e9e
  Issue Tracking, Mailing List, mailing-list, x_refsource_MLIST, NIST National Vulnerability Database
• www.oracle.com/security-alerts/cpujan2022.html
  Not Applicable, Third Party Advisory, x_refsource_MISC, NIST National Vulnerability Database
• lists.debian.org/debian-lts-announce/2020/12/msg00001.html
  Mailing List, Third Party Advisory, mailing-list, x_refsource_MLIST, NIST National Vulnerability Database
• www.oracle.com/security-alerts/cpuapr2022.html
  Not Applicable, Third Party Advisory, x_refsource_MISC, NIST National Vulnerability Database
• lists.apache.org/thread.html/redde3609b89b2a4ff18b536a06ef9a77deb93d47fda8ed28086fa8c3
  Issue Tracking, Mailing List, mailing-list, x_refsource_MLIST, NIST National Vulnerability Database
• www.debian.org/security/2020/dsa-4811
  Third Party Advisory, vendor-advisory, x_refsource_DEBIAN, NIST National Vulnerability Database

Elsewhere on this site

Related CVEs (same products)

• High CVE-2026-83206 Improper Access Control in Oracle Banking Corporate Lending Process Management Sep 15, 2026
• High CVE-2026-74761 Apache ActiveMQ Broker, Apache ActiveMQ All, Apache ActiveMQ: Spoofing of RemoveSubscription clientId Sep 9, 2026
• High CVE-2026-12996 A use-after-free in OpenVPN 2.6.0 through 2.6.20 and 2.7_alpha1 through 2.7.4 allows remote... Jul 30, 2026
• High CVE-2026-59878 Apache ActiveMQ AMQP, Apache ActiveMQ, Apache ActiveMQ All: AMQP NIO negative frame size validation bypass leading to DoS Jul 28, 2026
• Medium CVE-2026-61487 Apache ActiveMQ Broker, Apache ActiveMQ All, Apache ActiveMQ: Authorization bypass via temporary composite destinations Jul 28, 2026
• Critical CVE-2026-61097 Improper Access Control in Oracle Banking Trade Finance Process Management Jul 21, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

• No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
• No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
• No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2020-26217 is "Remote Code Execution in XStream", rated High. It affects Apache ActiveMQ (Apache Software Foundation); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 8.8 describes technical severity. EPSS 85.00% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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