LiveActive security incident?Get immediate response
CVE Record

CVE-2021-36979: Unicorn Engine 1.0.2 has an out-of-bounds write in tb_flush_armeb (called from cpu_arm_exec_armeb and tcg_c...

Unicorn Engine 1.0.2 has an out-of-bounds write in tb_flush_armeb (called from cpu_arm_exec_armeb and tcg_cpu_exec_armeb).

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

Security readout for executives and security teams

Plain-English summary

CVE-2021-36979 is a memory-safety flaw in Unicorn Engine 1.0.2. A malformed or unexpected ARM big-endian emulation workload could trigger an out-of-bounds write inside the process using Unicorn. Business urgency depends on whether Unicorn is embedded in exposed tooling or services.

Executive priority

Treat as a targeted dependency risk, not a broad emergency based on current evidence. Prioritize remediation where Unicorn processes untrusted files, firmware, binaries, or analysis inputs in production or security tooling.

Technical view

The CVE describes an out-of-bounds write in tb_flush_armeb, reached from cpu_arm_exec_armeb and tcg_cpu_exec_armeb. The source bundle identifies Unicorn Engine 1.0.2 and references OSS-Fuzz, an upstream commit, and a Fedora advisory, but provides no CVSS, CWE, or detailed impact rating.

Likely exposure

Exposure is likely limited to environments that install, package, or vendor Unicorn Engine 1.0.2, especially where ARM big-endian emulation processes untrusted inputs. The bundle does not identify broader affected products or downstream applications.

Exploitation context

No active exploitation is supported by the provided sources, and the CVE is not listed as KEV. The references point to OSS-Fuzz and a Chromium bug, suggesting discovery through fuzzing rather than public exploitation evidence.

Researcher notes

Evidence is sparse: no CVSS, CWE, exploit status, or fixed version is included in the bundle. Focus analysis on the ARM big-endian execution path and downstream packages that may have backported the referenced commit.

Mitigation direction

  • Inventory systems and applications for Unicorn Engine 1.0.2.
  • Apply vendor or distribution updates that incorporate the referenced upstream fix.
  • Review the Fedora advisory if using Fedora-packaged Unicorn Engine.
  • Limit untrusted emulation workloads until affected builds are replaced.
  • Check upstream Unicorn guidance for exact fixed versions.

Validation and detection

  • Confirm installed or vendored Unicorn Engine versions.
  • Verify builds include the referenced upstream commit or vendor advisory fix.
  • Review SBOMs and packaged dependencies for bundled Unicorn copies.
  • Test affected workflows after updating emulation libraries.
  • Document any exposed services that process untrusted emulation inputs.
Prepared
Confidence
medium
Sources
6

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-2021-36979 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
5Source 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.