Memory corruption in Apple WebKit/JavaScriptCore web content processing
CVE-2025-31277 is a WebKit/JavaScriptCore memory corruption vulnerability affecting Apple Safari and multiple Apple operating systems, including iOS, iPadOS, macOS, tvOS, visionOS, and watchOS. Apple states that processing maliciously crafted web content may lead to memory corruption and that the issue was addressed with improved memory handling. Supporting reporting further characterizes the bug as residing in JavaScriptCore and, in DarkSword exploitation, as a JIT optimization/type confusion issue used to obtain code execution in Safari’s renderer on devices running iOS versions prior to 18.6. WebKitGTK and WPE WebKit before 2.50.0 are also reported as affected.
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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.
Mitigation
If you can’t patch tonight, do this now.
Remediation
Patch, then assume compromise.
Exploits
No valid public exploits. Mallory filtered out 1 candidate as fakes, detection scripts, or README-only repos.
All candidate exploits were filtered out by Mallory's validation.
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.
Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
Recent activity
39 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
One of six CVEs in the DarkSword iOS exploit chain affecting older iOS 18 devices and tracked by CISA as actively exploited.
One of six vulnerabilities leveraged by the DarkSword exploit kit targeting iPhones and iPads running iOS 18.x; significant because DarkSword is described as actively exploited and broadly deployed.
One of six iOS vulnerabilities used by the DarkSword exploit kit to target iPhones running iOS 18.4 through 18.7; Apple shipped fixes in security updates and later expanded iOS 18.7.7 availability to protect more devices.
A JavaScriptCore memory corruption vulnerability used to achieve code execution inside Safari's renderer as part of the DarkSword iOS exploit chain.
The version that knows your environment.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.