Desktop: Use After Free
CVE-2022-23597 is a high-severity use after free vulnerability in Desktop from Element, with a CVSS 3.1 base score of 8.8 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. The record lists version 1.9.7 as the first without the flaw, so updating Desktop to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 1.51% chance of exploitation within 30 days, higher than 75% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Desktop to 1.9.7 or a later version.
- Read the advisory on github.com for workarounds and exact fixed builds.
- 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 NVD's product matching. 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
- 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:N/UI:R/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 8.3 | High | CNA (github.com) |
| CVSS 3.1 | 8.8 | High | NVD |
| CVSS 2.0 | 5.1 | Medium | NVD |
Official description
Element Desktop is a Matrix client for desktop platforms with Element Web at its core. Element Desktop before 1.9.7 is vulnerable to a remote program execution bug with user interaction. The exploit is non-trivial and requires clicking on a malicious link, followed by another button click. To the best of our knowledge, the vulnerability has never been exploited in the wild. If you are using Element Desktop < 1.9.7, we recommend upgrading at your earliest convenience. If successfully exploited, the vulnerability allows an attacker to specify a file path of a binary on the victim's computer which then gets executed. Notably, the attacker does *not* have the ability to specify program arguments. However, in certain unspecified configurations, the attacker may be able to specify an URI instead of a file path which then gets handled using standard platform mechanisms. These may allow exploiting further vulnerabilities in those mechanisms, potentially leading to arbitrary code execution.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use After Free
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.
How developers prevent this class of flaw
- Choose a language that provides automatic memory management.
- When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
- github.com/vector-im/element-desktop/security/advisories/GHSA-mjrg-9f8r-h3m7Third Party Advisory
Patches and release notes
Recent Use After Free vulnerabilities
- 7.8 High severity
- 7.8 High severity
Android Kernel Use-After-Free Exploited
- 7.8 High severity
- 8.8 High severity
Google Chromium V8 Use-After-Free Exploited
- 9.6 Critical severity
Google Chromium Portals Use-After-Free Exploited
- 9.6 Critical severity
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