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Not in CISA KEV
MEDIUM severity

CVE-2026-6874 copilot-api

MEDIUM

CVE-2026-6874 is a medium-severity (CVSS 4.3) CWE-350 vulnerability in copilot-api. No vendor fix is recorded yet; mitigation options are listed below.

copilot-api has Reliance on Reverse DNS Resolution for a Security-Critical Action

Published
Apr 23, 2026
Updated
May 5, 2026
Affected
1 pkg
Patched
None yet
Exploits
None indexed
Exploitation data as of Sep 21, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

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 CVE-2026-6874.

EPSS Exploitation Probability

via FIRST.org ↗
0.3%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs18th percentile — riskier than 18% of all scored CVEsHighest risk

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.

How urgent is this, really

CVE-2026-6874 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.

Where this sits among everything scored

Of 377,636 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.

Real-World Exposure

1 pkg affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

1other npm packages depend on this — each one inherits the vulnerability until it's patched upstream
copilot-apinpm
544downloads / week

Description

A vulnerability was determined in ericc-ch copilot-api up to 0.7.0. This impacts an unknown function of the file /token of the component Header Handler. Executing a manipulation of the argument Host can lead to reliance on reverse dns resolution. The attack may be performed from remote. The exploit has been publicly disclosed and may be utilized. The vendor was contacted early about this disclosure but did not respond in any way.

Affected Packages

1 total
EcosystemPackageVulnerable rangeFix
📦npmcopilot-apiall versionsNo fix

Detection & mitigation playbook

Open-source dependency
  1. Detect

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

  2. Remediation status

    No patched version of copilot-api has shipped for CVE-2026-6874 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.

  3. Mitigate without a patch

    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.

  4. How O3 protects you

    O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-6874 can be triaged on real exposure rather than presence alone.

Tailored to CVE-2026-6874. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

A vulnerability was determined in ericc-ch copilot-api up to 0.7.0. This impacts an unknown function of the file /token of the component Header Handler. Executing a manipulation of the argument Host can lead to reliance on reverse dns resolution. The attack may be performed from remote. The exploit has been publicly disclosed and may be utilized. The vendor was contacted early about this disclosure but did not respond in any way.
O3 Security · Impact-Aware SCA

Is CVE-2026-6874 in your dependencies?

O3 Security finds CVE-2026-6874 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

CVE-2026-6874: copilot-api (Medium 4.3) | O3 Security