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CVE Record

CVE-2021-27419: uClibc-ng Integer Overflow or Wraparound

uClibc-ng versions prior to 1.0.37 are vulnerable to integer wrap-around in functions malloc-simple. This improper memory assignment can lead to arbitrary memory allocation, resulting in unexpected behavior such as a crash or a remote code injection/execution.

HighCVSS 7.3Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

This is a memory-allocation flaw in uClibc-ng, a C library often used in constrained or embedded systems. A vulnerable build could mishandle allocation sizes and crash or allow code execution. Business urgency depends on whether exposed devices or firmware include uClibc-ng before 1.0.37.

Executive priority

Treat as high priority for internet-facing or operational devices using vulnerable uClibc-ng builds. If inventory cannot confirm library versions, prioritize discovery because product-level exposure is not provided in the sources.

Technical view

CVE-2021-27419 is a CWE-190 integer wrap-around in uClibc-ng malloc-simple before 1.0.37. The CVSS 3.1 vector is network-accessible, low complexity, no privileges, and no user interaction, with limited confidentiality, integrity, and availability impact rated 7.3.

Likely exposure

Exposure is most likely in products, firmware, or embedded systems that statically or dynamically include uClibc-ng before 1.0.37. The source bundle does not identify specific downstream products or deployments.

Exploitation context

The bundle does not show CISA KEV listing or cite active exploitation. The described impact includes crash and possible remote code injection or execution, but exploit availability is not evidenced here.

Researcher notes

Evidence supports a pre-1.0.37 uClibc-ng malloc-simple integer wrap-around with potential memory misallocation. Product attribution, exploit maturity, and concrete operational mitigations are incomplete in the provided bundle, so validation should focus on SBOM and firmware provenance.

Mitigation direction

  • Inventory firmware and software for uClibc-ng before 1.0.37.
  • Upgrade or rebuild with uClibc-ng 1.0.37 or later where supported.
  • Check vendor firmware advisories for affected downstream products.
  • Limit network exposure for services on affected embedded devices.
  • Prioritize vendor-supported patches over unsupported local changes.

Validation and detection

  • Confirm uClibc-ng version from SBOMs, build manifests, or firmware analysis.
  • Map vulnerable libraries to reachable services and device roles.
  • Verify vendor firmware notes reference the fixed uClibc-ng version.
  • Test patched firmware in staging before production rollout.
  • Document unresolved devices awaiting vendor guidance.
Prepared
Confidence
medium
Sources
4

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-190: Exact CWE lookup

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cve · low confidence lookup

CVE-2021-27419 mapping review

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.3 (3.1)
Known Exploited
No
Published

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

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
3Source 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
7.3CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L3.93.4Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

7.3High
CVSS 3.1 vector shape for CVE-2021-27419Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

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
uClibc-nguClibc-ngunspecifiedListed
Weakness

CWE details

CWE-190

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