LiveActive security incident?Get immediate response
CVE Record

CVE-2018-8778: 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 controlling the unpacking format (similar to format string vulnerabilities) can trigger a buffer under-read in the String#unpack method, resulting in a massive and controlled information disclosure.

UnknownCVSS not scoredNot KEV-listedUpdated
Discuss exposureBack to CVEs
Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2018-8778 is a Ruby flaw where attacker-controlled unpacking formats can make Ruby disclose data it should not expose. The public sources describe a potentially massive, controlled information disclosure in vulnerable Ruby versions, but they do not show active exploitation.

Executive priority

Treat this as a high-priority legacy runtime exposure, especially for Ruby services handling untrusted data. It is not KEV-listed in the bundle, so prioritize by reachable exposure and business criticality rather than assuming active attacks.

Technical view

The issue is a buffer under-read in Ruby String#unpack when the unpacking format is attacker controlled. Affected versions are 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.

Likely exposure

Exposure is likely where applications run the affected Ruby versions and allow untrusted input to influence String#unpack format strings. The bundle does not identify specific applications, packages, or deployment patterns beyond Ruby and distribution advisories.

Exploitation context

The source bundle says exploitation requires control of the unpacking format, similar to format string vulnerabilities. KEV is false, and the provided sources do not cite active exploitation or public weaponization.

Researcher notes

Key validation is whether an attacker can influence the unpack format, not merely whether String#unpack exists. CVSS and CWE data are absent in the bundle, so impact assessment relies on Ruby’s disclosure description and local reachability analysis.

Mitigation direction

  • Upgrade Ruby to the fixed versions or later supported releases.
  • Apply vendor security updates from your Linux distribution.
  • Prioritize internet-facing services processing untrusted binary or serialized data.
  • Review vendor advisories before changing unsupported legacy Ruby stacks.

Validation and detection

  • Inventory Ruby versions across hosts, containers, and build images.
  • Identify code paths using String#unpack with externally influenced formats.
  • Confirm OS package advisories are applied where Ruby is vendor-managed.
  • Regression test Ruby applications after runtime or package updates.
Prepared
Confidence
medium
Sources
10

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.

cve · low confidence lookup

CVE-2018-8778 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
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
15Source 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.