Cisco Webex Meetings: Deserialization of Untrusted Data
CVE-2022-20763 is a high-severity deserialization of untrusted data vulnerability in Cisco Webex Meetings from Cisco, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. There is no confirmed exploitation so far. EPSS estimates a 0.9% chance of exploitation within 30 days, higher than 60% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of Cisco Webex Meetings you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on tools.cisco.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Cisco | Cisco Webex Meetings | Not specified in the record | Not stated |
| Cisco | Webex Meetings Online | wbs42.2.1-1 | Not stated |
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
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 5.4 | Medium | CNA (cisco.com) |
| CVSS 3.1 | 8.8 | High | NVD |
| CVSS 2.0 | 6.5 | Medium | NVD |
Official description
A vulnerability in the login authorization components of Cisco Webex Meetings could allow an authenticated, remote attacker to inject arbitrary Java code. This vulnerability is due to improper deserialization of Java code within login requests. An attacker could exploit this vulnerability by sending malicious login requests to the Cisco Webex Meetings service. A successful exploit could allow the attacker to inject arbitrary Java code and take arbitrary actions within the Cisco Webex Meetings application.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Deserialization of Untrusted Data
The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.
How developers prevent this class of flaw
- If available, use the signing/sealing features of the programming language to assure that deserialized data has not been tainted. For example, a hash-based message authentication code (HMAC) could be used to ensure that data has not been modified.
- When deserializing data, populate a new object rather than just deserializing. The result is that the data flows through safe input validation and that the functions are safe.
- Explicitly define a final object() to prevent deserialization.
More Deserialization of Untrusted Data vulnerabilities (CWE-502)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Other vulnerabilities in Cisco Webex Meetings
- 9.8 Critical severity
Recent Deserialization of Untrusted Data vulnerabilities
- 7.8 High severity
- 9.8 Critical severity
- 8.8 High severity
- 7.2 High severity
- 7.2 High severity
- 7.5 High severity
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