CVE-2015-2978: Webservice-DIC yoyaku_v41 allows remote attackers to bypass authentication and complete a conference-room rese

Routine

MEDIUM 5.0DOWNGRADE

CVE-2015-2978 is a medium-severity flaw (CVSS 5.0) affecting yoyaku. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Webservice-DIC yoyaku_v41 allows remote attackers to bypass authentication and complete a conference-room reservation via unspecified vectors, as demonstrated by an "unintentional reservation."

Why this priority

No elevated risk signals yet

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

Risk facts

CVSS score	5.0 (Medium)
EPSS exploit chance	1.3% (top 30%)
CISA exploited list	No
Weakness	CWE-287
Published	2015-07-29
Last modified	2026-06-17

Publisher (CNA): JPCERT/CC · Vendor: webservice-dic

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

Am I affected?

Timeline

2015-07-29 14:59 UTCPublished CVE record published
2026-06-17 00:25 UTCUpdated Record last modified

webservice-dic yoyaku DOWNGRADE

Affected: 41

Fixed in: no fixed release known

Safe to downgrade to: a release before 41

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 41 (Debian / Ubuntu)

apt-cache madison yoyaku sudo apt install yoyaku=<VERSION_BEFORE_41> sudo apt-mark hold yoyaku

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

dnf --showduplicates list yoyaku sudo dnf downgrade yoyaku-<VERSION_BEFORE_41> sudo dnf versionlock add yoyaku

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-2015-2978?

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

Is CVE-2015-2978 being exploited?

CVE-2015-2978 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-2015-2978 affect?

CVE-2015-2978 affects yoyaku. Severity is medium (CVSS 5.0). Webservice-DIC yoyaku_v41 allows remote attackers to bypass authentication and complete a conference-room reservation via unspecified vectors, as demonstrated by an "unintentional reservation."

How urgent is CVE-2015-2978?

Priority 35/100. No elevated risk signals yet.

Related CVEs

CVE-2015-2979 HIGH 7.5 DOWNGRADE Webservice-DIC yoyaku_v41 allows remote attackers to execute arbitrary OS commands via unspecified vectors.
CVE-2015-2977 HIGH 7.5 DOWNGRADE Webservice-DIC yoyaku_v41 allows remote attackers to create arbitrary files, and consequently execute arbitrar

References

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