CVE-2004-0755: The FileStore capability in CGI::Session for Ruby before 1.8.1, and possibly PStore, creates files with insecu

Routine

LOW 2.1DOWNGRADE

CVE-2004-0755 is a low-severity flaw (CVSS 2.1) affecting ruby. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The FileStore capability in CGI::Session for Ruby before 1.8.1, and possibly PStore, creates files with insecure permissions, which can allow local users to steal session information and hijack sessions.

Why this priority

No elevated risk signals yet

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

Risk facts

CVSS score	2.1 (Low)
EPSS exploit chance	0.4% (top 70%)
CISA exploited list	No
Published	2004-10-20
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: yukihiro matsumoto

Last updated 2026-06-16 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2004-10-20 04:00 UTCPublished CVE record published
2026-06-16 22:06 UTCUpdated Record last modified

yukihiro matsumoto ruby DOWNGRADE

Affected: 1.6 · 1.8

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.6

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 1.6 (Debian / Ubuntu)

apt-cache madison ruby sudo apt install ruby=<VERSION_BEFORE_1.6> sudo apt-mark hold ruby

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

dnf --showduplicates list ruby sudo dnf downgrade ruby-<VERSION_BEFORE_1.6> sudo dnf versionlock add ruby

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-2004-0755?

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

Is CVE-2004-0755 being exploited?

CVE-2004-0755 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-2004-0755 affect?

CVE-2004-0755 affects ruby. Severity is low (CVSS 2.1). The FileStore capability in CGI::Session for Ruby before 1.8.1, and possibly PStore, creates files with insecure permissions, which can allow local users to steal session information and hijack sessions.

How urgent is CVE-2004-0755?

Priority 15/100. No elevated risk signals yet.

Software pages

Ruby vulnerabilities

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References

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