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CVE Record

CVE-2018-8777: In Ruby before 2.2.10, 2.3.x before 2.3.7, 2.4.x before 2.4.4, 2.5.x before 2.5.1, and 2.6.0-preview1, an a...

In Ruby before 2.2.10, 2.3.x before 2.3.7, 2.4.x before 2.4.4, 2.5.x before 2.5.1, and 2.6.0-preview1, an attacker can pass a large HTTP request with a crafted header to WEBrick server or a crafted body to WEBrick server/handler and cause a denial of service (memory consumption).

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This is a denial-of-service flaw in Ruby’s WEBrick web server. A vulnerable service can be forced to consume excessive memory when it receives an unusually large, specially formed HTTP request. The business impact is service instability or outage, not data theft or code execution based on the provided sources.

Executive priority

Address exposed WEBrick services promptly because the issue can cause outage with low attacker interaction. It is less urgent than remote code execution, but public services and customer-facing systems should be patched or moved off vulnerable Ruby versions.

Technical view

Ruby WEBrick before 2.2.10, 2.3.7, 2.4.4, 2.5.1, and 2.6.0-preview1 mishandles large HTTP requests with crafted headers or bodies, causing memory-consumption denial of service. Ruby and multiple Linux vendors issued security updates in 2018 and later.

Likely exposure

Exposure is most likely where Ruby applications run WEBrick or WEBrick handlers on vulnerable Ruby versions and accept untrusted HTTP traffic. Public-facing WEBrick services carry higher availability risk. The source bundle does not identify specific affected third-party applications.

Exploitation context

The bundle describes a request-based memory exhaustion condition but provides no evidence of active exploitation. The CVE is not listed as KEV in the supplied data. Treat it as a practical availability risk for exposed WEBrick deployments rather than confirmed widespread exploitation.

Researcher notes

The strongest evidence comes from Ruby’s advisory and release notes, supported by OS vendor advisories. The supplied CVE metadata lacks CVSS, CWE, and granular product CPEs, so validation should focus on Ruby version and actual WEBrick usage rather than package names alone.

Mitigation direction

  • Upgrade Ruby to a fixed or currently supported release.
  • Apply vendor security updates from Ubuntu, Debian, Red Hat, or SUSE as applicable.
  • Identify and retire internet-exposed WEBrick instances where possible.
  • Check vendor guidance for older distributions and unsupported Ruby branches.
  • Prioritize systems where WEBrick handles public or unauthenticated HTTP traffic.

Validation and detection

  • Inventory Ruby versions across servers, containers, and build images.
  • Identify applications that load or run WEBrick server components.
  • Confirm Ruby is at least 2.2.10, 2.3.7, 2.4.4, or 2.5.1.
  • Verify operating system Ruby packages include relevant vendor security updates.
  • Review monitoring for unexplained WEBrick memory growth or request-driven outages.
Prepared
Confidence
high
Sources
11

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.

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
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.

0CVSS vectors
0Timeline events
0ADP providers
18Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

No CWE listed

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