CVE-2018-16367: In OnlineJudge 2.0, the sandbox has an incorrect access control vulnerability that can write a file anywhere

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CRITICAL 9.9DOWNGRADE

CVE-2018-16367 is a critical-severity flaw (CVSS 9.9) affecting onlinejudge. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

In OnlineJudge 2.0, the sandbox has an incorrect access control vulnerability that can write a file anywhere. A user can write a directory listing to /tmp, and can leak file data with a #include.

Why this priority

Critical severity
Public exploit reference

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

Risk facts

CVSS score	9.9 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	2.2% (top 18%)
CISA exploited list	No
Weakness	CWE-22
Published	2018-09-02
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: qduoj

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

Am I affected?

Timeline

2018-09-02 22:29 UTCPublished CVE record published
2026-06-17 01:44 UTCUpdated Record last modified

qduoj onlinejudge DOWNGRADE

Affected: 2.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.0

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 2.0 (Debian / Ubuntu)

apt-cache madison onlinejudge sudo apt install onlinejudge=<VERSION_BEFORE_2.0> sudo apt-mark hold onlinejudge

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

dnf --showduplicates list onlinejudge sudo dnf downgrade onlinejudge-<VERSION_BEFORE_2.0> sudo dnf versionlock add onlinejudge

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-2018-16367?

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

Is CVE-2018-16367 being exploited?

CVE-2018-16367 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-2018-16367 affect?

CVE-2018-16367 affects onlinejudge. Severity is critical (CVSS 9.9). In OnlineJudge 2.0, the sandbox has an incorrect access control vulnerability that can write a file anywhere. A user can write a directory listing to /tmp, and can leak file data with a #include.

How urgent is CVE-2018-16367?

Priority 60/100. Critical severity; Public exploit reference

References

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