Security readout for executives and security teams
Plain-English summary
CVE-2021-31013 is an Apple font-processing memory disclosure issue. A maliciously crafted font could cause process memory to be exposed. Apple says improved bounds checking fixed it in named macOS, iOS, and iPadOS updates. No supplied source shows active exploitation.
Executive priority
Treat this as routine but timely Apple endpoint patching. The business risk is unauthorized memory disclosure from crafted fonts, with no supplied evidence of active exploitation. Prioritize systems that open external documents or receive untrusted files.
Technical view
The issue is an out-of-bounds read triggered while processing a crafted font. The described impact is disclosure of process memory, not code execution. Apple fixed it with improved bounds checking in macOS Monterey 12.1, macOS Big Sur 11.6.2, iOS 15.2, and iPadOS 15.2.
Likely exposure
Exposure is most relevant to Apple endpoints that can process untrusted fonts and have not been updated to the fixed releases named by Apple. The source bundle does not provide exact vulnerable version ranges or component names.
Exploitation context
The supplied record describes a malicious font as the trigger. CISA KEV status is false, and the provided sources do not claim exploitation in the wild or public weaponization.
Researcher notes
The public data is sparse: no CVSS, CWE, exact vulnerable ranges, or named vulnerable component are provided. Analysis should stay anchored to Apple’s advisory language and the CVE description until additional vendor detail is available.
Mitigation direction
- Update macOS Monterey systems to 12.1 or later.
- Update macOS Big Sur systems to 11.6.2 or later.
- Update iOS and iPadOS systems to 15.2 or later.
- Review Apple guidance for any platform-specific follow-up actions.
Validation and detection
- Inventory Apple devices and record OS versions.
- Confirm managed endpoints meet or exceed Apple’s fixed versions.
- Check vulnerability scanner findings against the CVE identifier.
- Review endpoint management reports for devices still processing untrusted files on older releases.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
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-2021-31013 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
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.
CVSS and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://support.apple.com/en-us/HT212976CVE reference · x_refsource_MISC
- https://support.apple.com/en-us/HT212978CVE reference · x_refsource_MISC
- https://support.apple.com/en-us/HT212979CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.