CVE-2023-27294: Improper neutralization of input during web page generation allows an authenticated attacker with access to a

Routine

MEDIUM 5.4DOWNGRADE

CVE-2023-27294 is a medium-severity flaw (CVSS 5.4) affecting opencats. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Improper neutralization of input during web page generation allows an authenticated attacker with access to a restricted account to submit malicious Javascript as the description for a calendar event, which would then be executed in other users' browsers if they browse to that event. This could result in stealing session tokens from users with higher permission levels or forcing users to make actions without their knowledge.

Why this priority

Public exploit reference

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

Risk facts

CVSS score	5.4 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	Required
EPSS exploit chance	0.5% (top 55%)
CISA exploited list	No
Weakness	CWE-79
Published	2023-02-28
Last modified	2026-06-17

Publisher (CNA): Tenable Network Security, Inc. · Vendor: opencats

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

Am I affected?

Timeline

2023-02-28 17:15 UTCPublished CVE record published
2026-06-17 05:44 UTCUpdated Record last modified

opencats opencats DOWNGRADE

Affected: 0.9.6

Fixed in: no fixed release known

Safe to downgrade to: a release before 0.9.6

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 0.9.6 (Debian / Ubuntu)

apt-cache madison opencats sudo apt install opencats=<VERSION_BEFORE_0.9.6> sudo apt-mark hold opencats

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

dnf --showduplicates list opencats sudo dnf downgrade opencats-<VERSION_BEFORE_0.9.6> sudo dnf versionlock add opencats

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-2023-27294?

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

Is CVE-2023-27294 being exploited?

CVE-2023-27294 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-2023-27294 affect?

CVE-2023-27294 affects opencats. Severity is medium (CVSS 5.4). Improper neutralization of input during web page generation allows an authenticated attacker with access to a restricted account to submit malicious Javascript as the description for a calendar event, which would then be executed in other u

How urgent is CVE-2023-27294?

Priority 35/100. Public exploit reference

Related CVEs

CVE-2023-27295 MEDIUM 5.4 DOWNGRADE Cross-site request forgery is facilitated by OpenCATS failure to require CSRF tokens in POST requests
CVE-2023-27293 MEDIUM 6.1 DOWNGRADE Improper neutralization of input during web page generation allows an unauthenticated attacker to submit malic
CVE-2023-27292 MEDIUM 5.4 DOWNGRADE An open redirect vulnerability exposes OpenCATS to template injection due to improper validation of user-suppl
CVE-2023-26847 MEDIUM 5.4 DOWNGRADE A stored cross-site scripting (XSS) vulnerability in OpenCATS v0.9.7 allows attackers to execute arbitrary web
CVE-2023-26846 MEDIUM 5.4 DOWNGRADE A stored cross-site scripting (XSS) vulnerability in OpenCATS v0.9.7 allows attackers to execute arbitrary web

References

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