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CVE Record

CVE-2021-28165: In Eclipse Jetty 7.2.2 to 9.4.38, 10.0.0.alpha0 to 10.0.1, and 11.0.0.alpha0 to 11.0.1, CPU usage can reach...

In Eclipse Jetty 7.2.2 to 9.4.38, 10.0.0.alpha0 to 10.0.1, and 11.0.0.alpha0 to 11.0.1, CPU usage can reach 100% upon receiving a large invalid TLS frame.

HighCVSS 7.5Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2021-28165 is a denial-of-service issue in Eclipse Jetty. A remote party can send a large invalid TLS frame and cause affected Jetty versions to consume full CPU, potentially disrupting services without exposing data or changing systems.

Executive priority

Treat as high priority for internet-facing or customer-facing services because it can cause outages without authentication. Prioritize by business criticality and whether Jetty directly handles TLS traffic.

Technical view

Affected Jetty ranges include 7.2.2 through 9.4.38, 10.0.0.alpha0 through 10.0.1, and 11.0.0.alpha0 through 11.0.1. The issue is resource exhaustion from handling malformed TLS input, scored CVSS 7.5 with network, low-complexity, unauthenticated availability impact.

Likely exposure

Exposure is most likely where applications or embedded products use affected Jetty versions and Jetty directly receives TLS traffic. Systems using Jetty only behind a separate TLS terminator may have different exposure and should verify actual traffic flow.

Exploitation context

The provided sources support remote unauthenticated denial of service, not data theft or code execution. CISA KEV status is false, and the bundle does not cite active exploitation evidence.

Researcher notes

The source bundle identifies CWE-400, CWE-551, and CWE-755, indicating resource management and exceptional-condition handling weakness. Evidence is strongest for availability impact and affected version ranges; exploit-in-the-wild evidence is not provided.

Mitigation direction

  • Inventory direct and transitive Jetty dependencies across applications and appliances.
  • Confirm affected versions against the Eclipse Jetty advisory before changing production.
  • Upgrade Jetty to a non-affected vendor-supported release.
  • For Jetty 9.x users, review 9.4.39-or-later upgrade paths cited by downstream projects.
  • Reduce direct internet exposure where Jetty terminates TLS until remediated.

Validation and detection

  • Check dependency manifests, SBOMs, and runtime libraries for affected Jetty versions.
  • Confirm whether Jetty receives TLS frames directly or sits behind TLS termination.
  • Review monitoring for unexplained Jetty CPU saturation during malformed traffic events.
  • Verify dependency scanners no longer report CVE-2021-28165 after remediation.
Prepared
Confidence
high
Sources
5

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-400: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
cwe · low confidence lookup

CWE-551: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
cwe · low confidence lookup

CWE-755: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2021-28165 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
High
CVSS
7.5 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
0Timeline events
0ADP providers
41Source links

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

7.5High
CVSS 3.1 vector shape for CVE-2021-28165Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
The Eclipse FoundationEclipse Jetty7.2.2, unspecified, 10.0.0.alpha0, unspecified, 11.0.0.alpha0, unspecifiedListed
Weakness

CWE details

CWE-400CWE-551CWE-755

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.