dbcve.org
FedoraOperating system · Fedoraproject

CVE-2021-30890

MEDIUM · 6.1 CVSS v3.1 Published 2021-08-24
Fix available
A fix is available. Upgrade to 8.1 / 12.0.1 or later.
See remediation →
68/100
Remediation priority · Elevated
Remotely reachable No privileges

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A logic issue was addressed with improved state management. This issue is fixed in macOS Monterey 12.0.1, iOS 15.1 and iPadOS 15.1, watchOS 8.1, tvOS 15.1. Processing maliciously crafted web content may lead to universal cross site scripting.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

CVE-2021-30890 is a logic flaw in WebKit (Apple's browser engine) where improper state management allows processing of maliciously crafted web content to trigger universal cross-site scripting (UXSS), enabling an attacker to execute arbitrary JavaScript in the context of any website visited by the victim.

MitigationApply the vendor-supplied patches by updating affected devices to macOS Monterey 12.0.1 or later, iOS/iPadOS 15.1 or later, watchOS 8.1 or later, and tvOS 15.1 or later. Until patched, avoid untrusted websites.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
FedoraOperating system
Affected:= 34= 35
Debian LinuxOperating system
Affected:= 10.0= 11.0
IpadosOperating system
Affected:< 15.1
Iphone OsOperating system
Affected:< 15.1
macOSOperating system
Affected:< 12.0.1
TvosOperating system
Affected:< 15.1
WatchosOperating system
Affected:< 8.1

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify your operating system
    Determine if the system is running macOS, iOS, iPadOS, tvOS, watchOS, Fedora, or Debian. On Apple devices, check Settings > General > About. On Linux, run 'uname -a' or check /etc/os-release.
    Affected if The OS is macOS below 12.0.1, iOS/iPadOS below 15.1, tvOS below 15.1, watchOS below 8.1, Fedora 34 or 35, or Debian 10.0 or 11.0.
  2. Confirm WebKit is in use
    WebKit is the browser engine used by Safari, iOS browsers, and many Linux browsers. On macOS, check Safari version via Safari > About Safari. On iOS/iPadOS, check Settings > Safari. On Linux, run 'dpkg -l | grep webkit' or 'rpm -qa | grep webkit' to list installed WebKit packages.
    Affected if Any WebKit-based browser or application is installed on an affected OS version.
  3. Check Safari version on macOS
    Open Safari and go to Safari > About Safari. Note the version number displayed.
    Affected if The version is below 15.1 (for macOS Big Sur 11.x) or the macOS version itself is below 12.0.1.
  4. Check WebKit package version on Linux
    On Fedora, run 'rpm -qa | grep -i webkit2'. On Debian, run 'dpkg -l | grep -i webkit2'. Note the version numbers shown.
    Affected if The webkit2gtk version corresponds to the vulnerable WebKit release bundled with the affected Fedora or Debian versions.

If the device runs an Apple OS version below the thresholds (iOS/iPadOS/tvOS/watchOS < 15.1, macOS < 12.0.1) or uses a vulnerable WebKit version on Fedora 34/35 or Debian 10.0/11.0, the environment is affected by this UXSS vulnerability.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 8.1 / 12.0.1 / 15.1 or later
Fixed in 8.112.0.115.1
Interim mitigation

Apply the vendor-supplied patches by updating affected devices to macOS Monterey 12.0.1 or later, iOS/iPadOS 15.1 or later, watchOS 8.1 or later, and tvOS 15.1 or later. Until patched, avoid untrusted websites.

Recommended fix High confidence

macOS 12.0.1+ | iOS 15.1+ | iPadOS 15.1+ | watchOS 8.1+ | tvOS 15.1+ | Fedora 36+ | Debian current

  1. For macOS: Upgrade to macOS Monterey 12.0.1 or later via System Preferences > Software Update
  2. For iOS/iPadOS: Upgrade to iOS 15.1 or later via Settings > General > Software Update
  3. For watchOS: Upgrade to watchOS 8.1 or later via the Watch app on iPhone
  4. For tvOS: Upgrade to tvOS 15.1 or later via Settings > System > Software Update
  5. For Fedora: Upgrade to a supported Fedora version (Fedora 34 and 35 are End-of-Life; migrate to Fedora 36+ or current supported release)
  6. For Debian: Update system packages via 'apt update && apt upgrade' to receive backported security patches for webkit2gtk or related packages
Caveat Major OS upgrades (e.g., to macOS Monterey) may have feature changes and hardware requirements; review Apple's release notes before upgrading

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Fedora Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA1.0 h
9.0 hours of engineering $1,600
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Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-30890 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data