GHSA-35wc-cvqg-78fp
GHSA-35wc-cvqg-78fp is a CWE-770 vulnerability in twig/intl-extra. O3 Security confirms whether GHSA-35wc-cvqg-78fp is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
twig/intl-extra: Unbounded formatter memoisation in keyed on template-controlled arguments
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-35wc-cvqg-78fp.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
twig/intl-extraReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
Description
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | twig/intl-extra | all versions | 3.26.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for twig/intl-extra. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update twig/intl-extra to 3.26.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-35wc-cvqg-78fp is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-35wc-cvqg-78fp is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-35wc-cvqg-78fp. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-35wc-cvqg-78fp in your dependencies?
O3 detects GHSA-35wc-cvqg-78fp across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.