Safari: Out-of-bounds Read
CVE-2026-28857 is a high-severity out-of-bounds read vulnerability in Safari from Apple, with a CVSS 3.1 base score of 8.8 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 26.4 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 0.69% chance of exploitation within 30 days, higher than 53% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Safari to 26.4 or a later version.
- Update iOS and iPadOS to 26.4 or a later version.
- Update macOS to 26.4 or a later version.
- Read the advisory on support.apple.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
- 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
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
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H. Scored by CNA.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 6.5 | Medium | CISA (ADP) |
| CVSS 3.1 | 8.8 | High | CNA |
Official description
The issue was addressed with improved memory handling. This issue is fixed in Safari 26.4, iOS 26.4 and iPadOS 26.4, macOS Tahoe 26.4, visionOS 26.4. Processing maliciously crafted web content may lead to an unexpected process crash.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Out-of-bounds Read
The product reads data past the end, or before the beginning, of the intended buffer.
How developers prevent this class of flaw
- Use a language that provides appropriate memory abstractions.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Other references
- access.redhat.com/errata/RHSA-2026:10702
- access.redhat.com/errata/RHSA-2026:11329
- access.redhat.com/errata/RHSA-2026:11814
- access.redhat.com/errata/RHSA-2026:13845
- access.redhat.com/errata/RHSA-2026:14659
- access.redhat.com/errata/RHSA-2026:16056
- access.redhat.com/errata/RHSA-2026:16695
- access.redhat.com/errata/RHSA-2026:19206
- access.redhat.com/errata/RHSA-2026:19535
- access.redhat.com/errata/RHSA-2026:22136
- access.redhat.com/errata/RHSA-2026:9692
- access.redhat.com/security/cve/CVE-2026-28857
- bugzilla.redhat.com/show_bug.cgi?id=2453004
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-28857.json
Other vulnerabilities in Safari
- 7.5 High severity
- 7.5 High severity
- 8.8 High severity
- 10.0 Critical severity
- 8.8 High severity
- 8.8 High severity
Recent Out-of-bounds Read vulnerabilities
- 7.1 High severity
- 7.1 High severity
- 7.1 High severity
- 7.1 High severity
- 7.1 High severity
- 7.1 High severity
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