CVE-2019-18850: TrevorC2 v1.1/v1.2 fails to prevent fingerprinting primarily via a discrepancy between response headers when r

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HIGH 7.5REMOTEDOWNGRADE

CVE-2019-18850 is a high-severity flaw (CVSS 7.5) affecting trevorc2. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

TrevorC2 v1.1/v1.2 fails to prevent fingerprinting primarily via a discrepancy between response headers when responding to different HTTP methods, also via predictible responses when accessing and interacting with the "SITE_PATH_QUERY".

Why this priority

High severity
Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.2% (top 32%)
CISA exploited list	No
Weakness	CWE-203, CWE-330
Published	2019-12-04
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: trustedsec

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2019-12-04 13:15 UTCPublished CVE record published
2026-06-17 02:25 UTCUpdated Record last modified

trustedsec trevorc2 DOWNGRADE

Affected: 1.1 · 1.2

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.1

1. Check installed version

apt-cache policy trevorc2 || rpm -q trevorc2 || trevorc2 --version

2. No fixed release: DOWNGRADE to a release before 1.1 (Debian / Ubuntu)

apt-cache madison trevorc2 sudo apt install trevorc2=<VERSION_BEFORE_1.1> sudo apt-mark hold trevorc2

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list trevorc2 sudo dnf downgrade trevorc2-<VERSION_BEFORE_1.1> sudo dnf versionlock add trevorc2

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2019-18850?

trevorc2: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2019-18850 being exploited?

CVE-2019-18850 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2019-18850 affect?

CVE-2019-18850 affects trevorc2. Severity is high (CVSS 7.5). TrevorC2 v1.1/v1.2 fails to prevent fingerprinting primarily via a discrepancy between response headers when responding to different HTTP methods, also via predictible responses when accessing and interacting with the "SITE_PATH_QUERY".

How urgent is CVE-2019-18850?

Priority 48/100. High severity; Remotely exploitable, no login, no user action

References

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