cmsimple: Improper Neutralization of Script-Related HTML Tags in a Web Page
CVE-2024-33423 is a high-severity improper neutralization of script-related HTML tags in a web page vulnerability in cmsimple, with a CVSS 3.1 base score of 7.4 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. Affected cmsimple versions: 5.15. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.56% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of cmsimple you run against the affected versions below, and install the vendor's latest release.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
- Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.
Affected products and versions
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- RequiredA user must take an action such as opening a file or link.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- NoneNothing can be modified.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N. Scored by CISA (ADP).
Official description
Cross-Site Scripting (XSS) vulnerability in the Settings menu of CMSimple v5.15 allows attackers to execute arbitrary web scripts or HTML via a crafted payload injected into the Logout parameter under the Language section.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Neutralization of Script-Related HTML Tags in a Web Page
The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes special characters such as <, >, and & that could be interpreted as web-scripting elements when they are sent to a downstream component that processes web pages.
How developers prevent this class of flaw
- With Struts, write all data from form beans with the bean's filter attribute set to true.
More Improper Neutralization of Script-Related HTML Tags in a Web Page vulnerabilities (CWE-80)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Technical write-ups (may include proof of concept)
- github.com/adiapera/xss_language_cmsimple_5.15Exploit, Third Party Advisory
Other vulnerabilities in cmsimple
- 8.8 High severity
- 7.5 High severity
- 7.2 High severity
Recent Improper Neutralization of Script-Related HTML Tags in a Web Page vulnerabilities
- 7.4 High severity
- 7.1 High severity
- 7.1 High severity
- 9.8 Critical severity
- 7.5 High severity
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