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High

Heap-based Buffer Overflow RCE in Apple Safari Regular Expression Duplicate Named Groups

IdentifiersCVE-2026-28847CWE-122

CVE-2026-28847 is a WebKit/Safari memory corruption vulnerability affecting Apple Safari and Apple platforms that ship the vulnerable WebKit component. Apple’s advisory states that processing maliciously crafted web content may lead to an unexpected process crash and that the issue was addressed with improved memory handling. Supporting content from ZDI provides more specific technical detail: the flaw exists in Safari’s handling of regular expression duplicate named groups, where improper validation of the length of user-supplied data before copying it into a heap-based buffer can trigger a heap-based buffer overflow. This can corrupt process memory while parsing attacker-controlled web content or a malicious file opened by the target.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Apple’s public advisory describes the impact as an unexpected process crash from maliciously crafted web content. However, the supporting ZDI content indicates the vulnerability is more severe: remote attackers can achieve arbitrary code execution on affected Safari installations. Exploitation would occur in the context of the current process, which for Safari/WebKit typically means code execution within the browser or associated content-processing process. At minimum, the flaw is a remotely triggerable denial-of-service via crash; with successful exploitation it provides remote code execution.

Mitigation

If you can’t patch tonight, do this now.

Until patches are fully deployed, reduce exposure by limiting use of Safari/WebKit for untrusted browsing, restricting access to untrusted websites and files, and applying standard browser hardening controls such as least-privilege user contexts and application isolation. Because exploitation requires the target to visit a malicious page or open a malicious file, user-awareness controls and URL/file filtering may reduce risk, but no vendor-provided workaround is available in the supplied content.

Remediation

Patch, then assume compromise.

Apply Apple’s fixes in the affected products: Safari 26.5; iOS 18.7.9 and iPadOS 18.7.9; iOS 26.5 and iPadOS 26.5; macOS Tahoe 26.5; tvOS 26.5; visionOS 26.5; and watchOS 26.5. Apple states the issue was addressed through improved memory handling. Where Safari is separately distributed, update via the Mac App Store or the relevant Apple software update channel. Prioritize patching internet-exposed and user-browsing endpoints.
PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType
AppleIosoperating_system
AppleIpadosoperating_system
AppleIphone Osoperating_system
AppleMacosoperating_system
AppleMacos Tahoeoperating_system
AppleTvosoperating_system
AppleVisionosoperating_system
AppleWatchosoperating_system
WebkitgtkWebkit2gtk3application

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

22 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

22 SOURCESView more in app
+8 more in the timeline
What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.
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Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity7

Community discussion across Reddit, Mastodon, and other social sources.

EXTERNAL REFERENCES
MITRE CVE
cve.org · CVE-2026-28847
NVD
nvd.nist.gov/vuln/detail/CVE-2026-28847
MITRE CWE · CWE-122
cwe.mitre.org
Vendor Advisory
support.apple.com/en-us/127110
Vendor Advisory
support.apple.com/en-us/127111
Vendor Advisory
support.apple.com/en-us/127115
Vendor Advisory
support.apple.com/en-us/127118
Vendor Advisory
support.apple.com/en-us/127119
Vendor Advisory
support.apple.com/en-us/127120
Vendor Advisory
support.apple.com/en-us/127121
zerodayinitiative.com
zerodayinitiative.com/advisories/ZDI-26-313