How severe is GHSA-99hj-44vg-hfcp?

No CVSS score has been assigned to GHSA-99hj-44vg-hfcp yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-99hj-44vg-hfcp?

GHSA-99hj-44vg-hfcp affects the following packages: github.com/fleetdm/fleet/v4 (Go). Ecosystems affected: Go.

How do I fix GHSA-99hj-44vg-hfcp?

Update github.com/fleetdm/fleet/v4 to 4.43.5-0.20260113202849-bbc1aef2987d or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-99hj-44vg-hfcp is resolved across your whole dependency graph.

How do I detect GHSA-99hj-44vg-hfcp in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/fleetdm/fleet/v4, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate GHSA-99hj-44vg-hfcp if there is no patch (or I can't update yet)?

Close the privilege gap rather than the entry point: audit which accounts, roles and service identities can reach the affected operation, drop the component to the least privilege it actually needs, and review file and directory permissions created by earlier installs — a default left in place is what makes this reachable.

Is GHSA-99hj-44vg-hfcp actively exploited in the wild?

No public exploit code has been indexed for GHSA-99hj-44vg-hfcp 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-99hj-44vg-hfcp?

GHSA-99hj-44vg-hfcp has an EPSS (Exploit Prediction Scoring System) score of 0.5%, placing it in the 39th 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 GHSA-99hj-44vg-hfcp?

GHSA-99hj-44vg-hfcp is classified as CWE-770 (CWE-770). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-99hj-44vg-hfcp published, and has it been updated?

GHSA-99hj-44vg-hfcp was published on March 27, 2026 and was last updated on April 2, 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

GHSA-99hj-44vg-hfcp — v4

GHSA-99hj-44vg-hfcp is a CWE-770 vulnerability in github.com/fleetdm/fleet/v4. A fix is available for github.com/fleetdm/fleet/v4 — see the affected versions and patch details below.

Fleet's unbounded request body read allows remote Denial of Service

Also known asCVE-2026-26061GO-2026-4889

Published

Mar 27, 2026

Updated

Apr 2, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Sep 26, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
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-99hj-44vg-hfcp.

EPSS Exploitation Probability

via FIRST.org ↗

0.5%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs39th percentile — riskier than 39% 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/fleetdm/fleet/v4

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

Summary

Fleet contained multiple unauthenticated HTTP endpoints that read request bodies without enforcing a size limit. An unauthenticated attacker could exploit this behavior by sending large or repeated HTTP payloads, causing excessive memory allocation and resulting in a denial-of-service (DoS) condition.

Impact

An unauthenticated attacker could cause the Fleet server process to exhaust available memory and restart by sending oversized or repeated HTTP requests to affected endpoints.

This vulnerability impacts availability only. There is:

No exposure of sensitive data
No authentication bypass
No privilege escalation
No integrity impact

Workarounds

If upgrading immediately is not possible, the following mitigations can reduce exposure:

Apply request body size limits at a reverse proxy or load balancer (e.g., NGINX, Envoy).
Restrict network access to endpoints to known IP ranges where feasible.
Monitor memory usage and restart frequency for abnormal patterns.

For More Information

If there are any questions or concerns about this advisory, please contact us at:

Email Fleet at [email protected]

Credits

Fleet thanks @fuzzztf for responsibly reporting this issue.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/fleetdm/fleet/v4`	all versions	4.43.5-0.20260113202849-bbc1aef2987d`go get github.com/fleetdm/fleet/v4@v4.43.5-0.20260113202849-bbc1aef2987d`

Affected Products

1 product · 1 configurations

Application

fleetfleetdm

< 4.81.0

range

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/fleetdm/fleet/v4, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/fleetdm/fleet/v4 to 4.43.5-0.20260113202849-bbc1aef2987d or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-99hj-44vg-hfcp is resolved across your whole dependency graph.
Workarounds
Close the privilege gap rather than the entry point: audit which accounts, roles and service identities can reach the affected operation, drop the component to the least privilege it actually needs, and review file and directory permissions created by earlier installs — a default left in place is what makes this reachable.

Frequently Asked Questions

### Summary Fleet contained multiple unauthenticated HTTP endpoints that read request bodies without enforcing a size limit. An unauthenticated attacker could exploit this behavior by sending large or repeated HTTP payloads, causing excessive memory allocation and resulting in a denial-of-service (DoS) condition. ### Impact An unauthenticated attacker could cause the Fleet server process to exhaust available memory and restart by sending oversized or repeated HTTP requests to affected endpoints. This vulnerability impacts **availability only**. There is: - No exposure of sensitive data -

O3 Security · Impact-Aware SCA

Is GHSA-99hj-44vg-hfcp in your dependencies?

Find it across Go, including transitive dependencies.

Scan my dependencies How O3 SCA works

GHSA-99hj-44vg-hfcp — v4

Exploitation Status

No confirmed exploitation observed yet

EPSS Exploitation Probability

Real-World Exposure

Description

Summary

Impact

Workarounds

For More Information

Credits

Affected Packages

Affected Products

Detection & mitigation playbook

Detect

Fix

Workarounds

Frequently Asked Questions

Is GHSA-99hj-44vg-hfcp in your dependencies?