How severe is GHSA-mh55-gqvf-xfwm?

No CVSS score has been assigned to GHSA-mh55-gqvf-xfwm yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-mh55-gqvf-xfwm?

GHSA-mh55-gqvf-xfwm affects the following packages: github.com/rs/cors (Go). Ecosystems affected: Go.

How do I fix GHSA-mh55-gqvf-xfwm?

Update github.com/rs/cors to 1.11.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-mh55-gqvf-xfwm is resolved across your whole dependency graph.

How do I detect GHSA-mh55-gqvf-xfwm in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/rs/cors, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate GHSA-mh55-gqvf-xfwm if there is no patch (or I can't update yet)?

Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Is GHSA-mh55-gqvf-xfwm actively exploited in the wild?

No public exploit code has been indexed for GHSA-mh55-gqvf-xfwm 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 GHSA-mh55-gqvf-xfwm?

GHSA-mh55-gqvf-xfwm has an EPSS (Exploit Prediction Scoring System) score of 0.7%, placing it in the 53th 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 GHSA-mh55-gqvf-xfwm published, and has it been updated?

GHSA-mh55-gqvf-xfwm was published on July 5, 2024 and was last updated on September 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

Not in CISA KEV

Denial of service via malicious preflight requests in github.com/rs/corsGHSA-mh55-gqvf-xfwm

Fix: rs/cors#171

GHSA-mh55-gqvf-xfwm is a security vulnerability in github.com/rs/cors. A fix is available for github.com/rs/cors — see the affected versions and patch details below.

Also known asCVE-2025-47908GO-2024-2883

Published

Jul 5, 2024

Updated

Sep 10, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 11, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

Proof-of-concept exploit code exists

CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.

Exploitation and automatability from CISA’s SSVC triage for GHSA-mh55-gqvf-xfwm.

EPSS Exploitation Probability

via FIRST.org ↗

0.7%probability of exploitation in next 30 days

Lower Risk+0.05%

Lower risk than most CVEs53th percentile — riskier than 53% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

🐹github.com/rs/cors

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

Middleware causes a prohibitive amount of heap allocations when processing malicious preflight requests that include a Access-Control-Request-Headers (ACRH) header whose value contains many commas. This behavior can be abused by attackers to produce undue load on the middleware/server as an attempt to cause a denial of service.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/rs/cors`	≥ 1.9.0&&< 1.11.0	1.11.0`go get github.com/rs/cors@v1.11.0`

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/rs/cors, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/rs/cors to 1.11.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-mh55-gqvf-xfwm is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatModerate

Workaround published by Red Hat

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.

Source: Red Hat security advisory for GHSA-mh55-gqvf-xfwm (CC BY 4.0)

Frequently Asked Questions

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