CyberSecBulletin
CVE-2026-64713NVD status: Analyzed

Safari: Observable Discrepancy

Published Updated By the CyberSecBulletin desk

CVE-2026-64713 is a high-severity observable discrepancy vulnerability in Safari from Apple, with a CVSS 3.1 base score of 8.1 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. The record lists version 26.6 as the first without the flaw, so updating Safari to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.47% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Safari to 26.6 or a later version.
  2. Update iOS and iPadOS to 26.6 or a later version.
  3. Update macOS to 26.6 or a later version.
  4. Read the advisory on support.apple.com for workarounds and exact fixed builds.
  5. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
  6. Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.

Affected products and versions

VendorProductAffected versionsFixed in
AppleSafaribefore 26.626.6
AppleiOS and iPadOSbefore 26.626.6
ApplemacOSbefore 26.626.6
AppletvOSbefore 26.626.6
ApplevisionOSbefore 26.626.6
ApplewatchOSbefore 26.626.6
AppleiPadOSbefore 26.626.6
AppleIphone OSbefore 26.626.6

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
RequiredA user must take an action such as opening a file or link.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
NoneAvailability is not affected.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N. Scored by CISA (ADP).

Official description

This issue was addressed with improved checks. This issue is fixed in Safari 26.6, iOS 26.6 and iPadOS 26.6, macOS Tahoe 26.6, tvOS 26.6, visionOS 26.6, watchOS 26.6. Websites may know if the user has visited a given link.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Observable Discrepancy

The product behaves differently or sends different responses under different circumstances in a way that is observable to an unauthorized actor.

How developers prevent this class of flaw

  • Compartmentalize the system to have safe areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area. Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.

More Observable Discrepancy vulnerabilities (CWE-203)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in Safari

All Safari vulnerabilities

Recent Observable Discrepancy vulnerabilities

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