Security readout for executives and security teams
Plain-English summary
This is a browser memory-safety flaw in Chrome Autofill on Android. A user visiting a malicious HTML page could trigger out-of-bounds memory access. The source bundle identifies affected Chrome on Android versions before 91.0.4472.77. No source provided here shows active exploitation.
Executive priority
Treat as a high-priority browser update issue, especially for Android fleets. It is remotely reachable through web content, but the provided evidence does not show active exploitation or a public exploit.
Technical view
CVE-2021-30521 is a heap buffer overflow in Chrome Autofill on Android. The documented attack vector is a crafted HTML page causing out-of-bounds memory access. CVSS and CWE data are not included in the bundle, and the Chromium bug details may be restricted.
Likely exposure
Exposure is most likely on Android devices running Google Chrome before 91.0.4472.77. Gentoo and Fedora advisories indicate Chromium package updates also mattered for some Linux environments, but this bundle does not define their exact affected version ranges.
Exploitation context
The public description supports remote triggering through a crafted HTML page. The CVE is not listed as KEV in the bundle, and no cited source here claims exploitation in the wild.
Researcher notes
The bundle lacks CVSS, CWE, and detailed root-cause notes. The strongest confirmed facts are component, platform, fixed-version boundary, and crafted-HTML trigger. Avoid assuming code execution or exploit maturity beyond the documented out-of-bounds memory access.
Mitigation direction
- Update Chrome on Android to 91.0.4472.77 or later.
- Apply current vendor-supported Chrome or Chromium packages on managed systems.
- Follow Gentoo and Fedora advisory instructions where those distributions are in scope.
- Prioritize browser updates on mobile fleets and shared-risk user groups.
Validation and detection
- Inventory Android Chrome versions across managed devices.
- Flag Chrome versions older than 91.0.4472.77.
- Check Linux Chromium package status against Gentoo or Fedora advisories if used.
- Confirm browser update policy reaches unmanaged or BYOD Android devices.
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-2021-30521 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://crbug.com/1208721CVE reference · x_refsource_MISC
- https://chromereleases.googleblog.com/2021/05/stable-channel-update-for-desktop_25.htmlCVE reference · x_refsource_MISC
- GLSA-202107-06CVE reference · vendor-advisory, x_refsource_GENTOO
- FEDORA-2021-f94dadff78CVE reference · vendor-advisory, x_refsource_FEDORA
- FEDORA-2021-ca58c57bdfCVE reference · vendor-advisory, x_refsource_FEDORA
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.