Security readout for executives and security teams
Plain-English summary
This Apple iOS flaw can let malicious web content run code on a device after user interaction. Apple fixed it in iOS 12.5.4 and reported possible active exploitation. CISA also lists it in the Known Exploited Vulnerabilities catalog, so unpatched legacy iOS devices deserve priority attention.
Executive priority
Treat this as a priority patching issue for any legacy iOS estate. The business concern is device compromise from malicious web content, with confirmed KEV status and high impact if a vulnerable device is targeted.
Technical view
CVE-2021-30761 is a WebKit-related memory corruption issue, tracked as CWE-787, addressed through improved state management. The CVSS 3.1 score is 8.8 with network attack vector, low complexity, no privileges required, user interaction required, and high confidentiality, integrity, and availability impact.
Likely exposure
Exposure is most likely on Apple iOS devices that have not received the iOS 12.5.4 security update. The source bundle does not identify exact device models or all vulnerable version ranges beyond Apple iOS and the fixed release.
Exploitation context
Active exploitation is supported by Apple’s statement that it was aware of a report the issue may have been actively exploited, and by CISA KEV inclusion. Public sources here do not describe exploit scale, targets, or technical exploit details.
Researcher notes
The available bundle supports memory corruption, arbitrary code execution through malicious web content, CWE-787, iOS 12.5.4 fix, and exploitation signal. It does not provide crash details, proof-of-concept material, affected model lists, or indicators of compromise.
Mitigation direction
- Install iOS 12.5.4 where applicable.
- Check Apple guidance for later supported update paths.
- Prioritize remediation of devices used by executives and high-risk staff.
- Track this as a CISA KEV remediation item.
- Retire or restrict devices that cannot receive the fixed release.
Validation and detection
- Inventory iOS devices and recorded OS versions.
- Confirm whether each device has iOS 12.5.4 or later applicable updates.
- Flag unsupported or unmanaged devices for follow-up.
- Verify mobile device management compliance reporting.
- Document exceptions and compensating restrictions.
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.
CWE-787: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-30761 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
- High
- CVSS
- 8.8 (3.1)
- Known Exploited
- Yes
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
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.
CISA KEV status
CVSS vector scores
1 official scoreWe 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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H2.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
8.8HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://support.apple.com/en-us/HT212548CVE reference · x_refsource_MISC
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-30761CVE reference · government-resource
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.
Out-of-bounds Write
Out-of-bounds Write represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.