How severe is CVE-2021-23772?

CVE-2021-23772 has a CVSS score of 8.8/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2021-23772?

CVE-2021-23772 affects the following packages: github.com/kataras/iris/v12 (Go), github.com/kataras/iris (Go). Ecosystems affected: Go.

How do I fix CVE-2021-23772?

Update github.com/kataras/iris/v12 to 12.2.0-alpha8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-23772 is resolved across your whole dependency graph.

How do I detect CVE-2021-23772 in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/kataras/iris/v12. 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-2021-23772 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-2021-23772?

O3 pinpoints whether CVE-2021-23772 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-2021-23772 actively exploited in the wild?

Yes. There are 2 known exploit references for CVE-2021-23772, including 2 in-the-wild exploitations observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2021-23772?

CVE-2021-23772 has an EPSS (Exploit Prediction Scoring System) score of 1.8%, placing it in the 76th 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.

When was CVE-2021-23772 published, and has it been updated?

CVE-2021-23772 was published on December 24, 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.

🐹 Go

CVE-2021-23772

HIGH

Link Following in Iris

Also known asGHSA-jcxc-rh6w-wf49GO-2022-0272

Published

Dec 24, 2021

Updated

Apr 10, 2026

Affected

2 pkgs

Patched

1 / 2

Exploits

2 known

EPSS Exploitation Probability

via FIRST.org ↗

1.8%probability of exploitation in next 30 days

Lower Risk76th percentile+0.94%

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

🐹github.com/kataras/iris/v12🐹github.com/kataras/iris

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

This affects all versions of package github.com/kataras/iris; all versions of package github.com/kataras/iris/v12. The unsafe handling of file names during upload using UploadFormFiles method may enable attackers to write to arbitrary locations outside the designated target folder.

Affected Packages

2 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/kataras/iris/v12`	all versions	12.2.0-alpha8
🐹Go	`github.com/kataras/iris`	all versions	No fix

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

This affects all versions of package github.com/kataras/iris; all versio…

snyk.ioNVDJan 2022

This affects all versions of package github.com/kataras/iris; all versio…

snyk.ioNVDJan 2022

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/kataras/iris/v12. 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 github.com/kataras/iris/v12 to 12.2.0-alpha8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-23772 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-2021-23772 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-2021-23772. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2021-23772 in your dependencies?

O3 detects CVE-2021-23772 across Go 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