Apple Multiple Products Buffer Overflow
CVE-2025-31277 is a high-severity improper restriction of operations within the bounds of a memory buffer 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 18.6 as the first without the flaw, so updating Safari to that release or later removes the exposure. CISA added it to the Known Exploited Vulnerabilities catalogue on March 20, 2026, which means attacks have been observed in the wild.
Attackers are already exploiting this vulnerability, according to CISA.
What to do
- Update Safari to 18.6 or a later version.
- Update iOS and iPadOS to 18.6 or a later version.
- Update macOS to 15.6 or a later version.
- CISA's required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
- 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; 7 further products are omitted here. 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 | 8.8 | High | 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 18.6, iOS 18.6 and iPadOS 18.6, macOS Sequoia 15.6, tvOS 18.6, visionOS 2.6, watchOS 11.6. Processing maliciously crafted web content may lead to memory corruption.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Restriction of Operations within the Bounds of a Memory Buffer
The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary.
How developers prevent this class of flaw
- Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer. Be wary that a language's interface to native code may still be subject to overflows, even if the language itself is theoretically safe.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Examples include the Safe C String Library (SafeStr) by Messier and Viega, and the Strsafe.h library from Microsoft. These libraries provide safer versions of overflow-prone string-handling functions.
- Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND discusses canary-based detection in detail.
Timeline
- CVE record published.
- Added to CISA's Known Exploited Vulnerabilities catalogue.
- CISA published its SSVC assessment (exploitation: active, automatable: no, technical impact: total).
- Deadline for US federal agencies to remediate, set by CISA.
- Record last changed materially (score, affected products, status or references).
References
Advisories
- support.apple.com/en-us/124147Release Notes
- support.apple.com/en-us/124149Release Notes
- support.apple.com/en-us/124152Release Notes
- support.apple.com/en-us/124153Release Notes
- support.apple.com/en-us/124154Release Notes
- support.apple.com/en-us/124155Release Notes
Third-party and government advisories
- seclists.org/fulldisclosure/2025/Aug/0Mailing List, Third Party Advisory
- seclists.org/fulldisclosure/2025/Jul/30Mailing List, Third Party Advisory
- seclists.org/fulldisclosure/2025/Jul/32Mailing List, Third Party Advisory
- seclists.org/fulldisclosure/2025/Jul/36Mailing List, Third Party Advisory
- access.redhat.com/errata/RHSA-2025:17643Third Party Advisory
- access.redhat.com/errata/RHSA-2025:17741Third Party Advisory
- access.redhat.com/errata/RHSA-2025:17743Third Party Advisory
- access.redhat.com/errata/RHSA-2025:17802Third Party Advisory
- access.redhat.com/errata/RHSA-2025:17807Third Party Advisory
- access.redhat.com/errata/RHSA-2025:18097Third Party Advisory
- access.redhat.com/errata/RHSA-2025:19109Third Party Advisory
- access.redhat.com/errata/RHSA-2025:19157Third Party Advisory
- access.redhat.com/errata/RHSA-2025:19165Third Party Advisory
- access.redhat.com/errata/RHSA-2025:19352Third Party Advisory
- access.redhat.com/security/cve/CVE-2025-31277Third Party Advisory
Other references
- cloud.google.com/blog/topics/threat-intelligence/darksword-ios-exploit-chain/Technical Description
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 Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerabilities
- 8.2 High severity
- 7.8 High severity
- 8.8 High severity
- 8.8 High severity
- 9.8 Critical severity
- 8.8 High severity
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