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PatchSiren cyber security CVE debrief

CVE-2017-6056 Canonical CVE debrief

CVE-2017-6056 is a network-reachable denial-of-service issue in Apache Tomcat's HTTPS request processing that can drive the server into an infinite loop. NVD rates it HIGH (CVSS 3.0: AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H) and maps it to CWE-835. The issue is described as a backporting mistake: a fix for CVE-2016-6816 was applied without the related Tomcat bug 57544 fix, affecting packaged deployments such as Debian and Ubuntu.

Vendor
Canonical
Product
Unknown
CVSS
HIGH 7.5
CISA KEV
Not listed in stored evidence
Original CVE published
2017-02-17
Original CVE updated
2026-05-13
Advisory published
2017-02-17
Advisory updated
2026-05-13

Who should care

System administrators and platform teams running Apache Tomcat from affected Debian or Ubuntu package builds, especially services that accept HTTPS traffic.

Technical summary

The vulnerability affects distro-packaged Tomcat builds where HTTPS request handling can enter an infinite loop because only part of the upstream fix set was backported. NVD lists Ubuntu 12.04 LTS, Ubuntu 14.04 LTS, and Debian Linux 8.0 as vulnerable CPEs. The CVSS vector indicates availability-only impact, with no confidentiality or integrity impact recorded.

Defensive priority

High for exposed Tomcat HTTPS services on affected Debian or Ubuntu packages; the flaw is remotely triggerable and can exhaust availability without authentication or user interaction.

Recommended defensive actions

  • Apply the patched Tomcat packages provided by your operating system vendor or distribution security advisories.
  • Verify installed package versions against the vulnerable CPE scope listed by NVD, especially Ubuntu 12.04/14.04 LTS and Debian 8.0 builds.
  • Prioritize remediation for any externally reachable HTTPS Tomcat instances.
  • Monitor affected hosts for service hangs, abnormal CPU consumption, or repeated restarts until patching is complete.
  • If you rely on downstream backports, confirm that the full related fix set was applied, not just a single CVE patch.

Evidence notes

The supplied corpus shows a public disclosure date of 2017-02-17 and an NVD record modified on 2026-05-13. NVD's CVSS vector is AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H and the primary weakness is CWE-835. The record's references include Debian security advisories, Red Hat errata, and Apache Bugzilla 60578, and the CVE description states the DoS resulted from backporting the CVE-2016-6816 fix without the Tomcat bug 57544 fix.

Sources and references

Verified primary and authoritative sources

  • CVE-2017-6056 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2017-6056

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2017-6056 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2017-6056

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.