How severe is CVE-2021-29487?

CVE-2021-29487 has a CVSS score of 7.4/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2021-29487?

CVE-2021-29487 affects the following packages: october/system (Packagist), october/system (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2021-29487?

Update october/system to 1.0.472 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-29487 is resolved across your whole dependency graph.

How do I detect CVE-2021-29487 in my Packagist dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for october/system. 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.

How do I mitigate CVE-2021-29487 if there is no patch (or I can't update yet)?

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 does O3 Security protect against CVE-2021-29487?

O3 pinpoints whether CVE-2021-29487 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2021-29487 actively exploited in the wild?

No public exploit code has been indexed for CVE-2021-29487 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2021-29487?

CVE-2021-29487 has an EPSS (Exploit Prediction Scoring System) score of 0.9%, placing it in the 55th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2021-29487?

CVE-2021-29487 is classified as Improper Authentication (CWE-287). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2021-29487 published, and has it been updated?

CVE-2021-29487 was published on August 26, 2021 and was last updated on April 10, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CVE-2021-29487: October CMS auth bypass and account takeover (H…

EPSS Exploitation Probability

via FIRST.org ↗

0.9%probability of exploitation in next 30 days

Lower Risk55th percentile+0.39%

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.

Blast Radius

2 pkgs affected

🐘october/system🐘october/system

Real-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

octobercms in a CMS platform based on the Laravel PHP Framework. In affected versions of the october/system package an attacker can exploit this vulnerability to bypass authentication and takeover of and user account on an October CMS server. The vulnerability is exploitable by unauthenticated users via a specially crafted request. This only affects frontend users and the attacker must obtain a Laravel secret key for cookie encryption and signing in order to exploit this vulnerability. The issue has been patched in Build 472 and v1.1.5.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`october/system`	all versions	1.0.472
🐘Packagist	`october/system`	≥ 1.1.1&&< 1.1.5	1.1.5

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for october/system. 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 october/system to 1.0.472 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-29487 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 CVE-2021-29487 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 CVE-2021-29487. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

octobercms in a CMS platform based on the Laravel PHP Framework. In affected versions of the october/system package an attacker can exploit this vulnerability to bypass authentication and takeover of and user account on an October CMS server. The vulnerability is exploitable by unauthenticated users via a specially crafted request. This only affects frontend users and the attacker must obtain a Laravel secret key for cookie encryption and signing in order to exploit this vulnerability. The issue has been patched in Build 472 and v1.1.5.

O3 Security · Impact-Aware SCA

Is CVE-2021-29487 in your dependencies?

O3 detects CVE-2021-29487 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works

CVE-2021-29487