Summary
twig/intl-extra: Unbounded formatter memoisation in keyed on template-controlled arguments
Description
IntlExtension memoises every \IntlDateFormatter and \NumberFormatter it creates in instance-level arrays keyed on a hash that includes locale, pattern, attrs and other values that are ordinary named arguments of the format_datetime / format_date / format_time / format_number / format_currency filters. There is no size limit and no eviction.
A template that iterates over many distinct pattern (or locale, or grouping_used, ...) values therefore allocates one ICU formatter object per distinct value and pins it for the entire lifetime of the Twig\Environment. Because ICU allocates its backing buffers outside the Zend memory manager, this growth is not bounded by memory_limit. On long-running runtimes (RoadRunner, Swoole, FrankenPHP worker mode, ReactPHP) where the Environment outlives a single request, the cache also accumulates across requests.
Resolution
The formatter caches are now bounded in size (100 entries each) and evict on a FIFO basis.
Credits
Twig would like to thank Claude Mythos Preview (via Project Glasswing) for reporting the issue and providing the fix.
Impact
The application allocates resources such as memory, threads, or file descriptors based on untrusted input without enforcing a cap. Typical impact: resource exhaustion leading to denial of service.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2026-46629? CVE-2026-46629 is a low-severity allocation of resources without limits or throttling vulnerability in twig/intl-extra (composer), affecting versions < 3.26.0. It is fixed in 3.26.0. The application allocates resources such as memory, threads, or file descriptors based on untrusted input without enforcing a cap.
- Which versions of twig/intl-extra are affected by CVE-2026-46629? twig/intl-extra (composer) versions < 3.26.0 is affected.
- Is there a fix for CVE-2026-46629? Yes. CVE-2026-46629 is fixed in 3.26.0. Upgrade to this version or later.
- Is CVE-2026-46629 exploitable, and should I be worried? Whether CVE-2026-46629 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-46629 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-46629? Upgrade
twig/intl-extrato 3.26.0 or later.