zulip: Concurrent Execution using Shared Resource with Improper Synchronization
CVE-2022-24751 is a high-severity concurrent execution using shared resource with improper synchronization vulnerability in zulip, 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, without any action from a user. Affected zulip versions: >= 4.0, < 4.11. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.95% chance of exploitation within 30 days, higher than 62% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of zulip you run against the affected versions below, and install the vendor's latest release.
- 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.
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
- HighSuccess depends on conditions outside the attacker's control.
- Privileges required
- NoneNo account or login is needed.
- 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
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 5.4 | Medium | CNA (github.com) |
| CVSS 3.1 | 7.4 | High | NVD |
| CVSS 2.0 | 5.8 | Medium | NVD |
Official description
Zulip is an open source group chat application. Starting with version 4.0 and prior to version 4.11, Zulip is vulnerable to a race condition during account deactivation, where a simultaneous access by the user being deactivated may, in rare cases, allow continued access by the deactivated user. A patch is available in version 4.11 on the 4.x branch and version 5.0-rc1 on the 5.x branch. Upgrading to a fixed version will, as a side effect, deactivate any cached sessions that may have been leaked through this bug. There are currently no known workarounds.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Concurrent Execution using Shared Resource with Improper Synchronization
The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.
How developers prevent this class of flaw
- In languages that support it, use synchronization primitives. Only wrap these around critical code to minimize the impact on performance.
- Use thread-safe capabilities such as the data access abstraction in Spring.
- Minimize the usage of shared resources in order to remove as much complexity as possible from the control flow and to reduce the likelihood of unexpected conditions occurring. Additionally, this will minimize the amount of synchronization necessary and may even help to reduce the likelihood of a denial of service where an attacker may be able to repeatedly trigger a critical section (CWE-400).
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
- github.com/zulip/zulip/security/advisories/GHSA-6v98-m5x5-phqjThird Party Advisory
Patches and release notes
- github.com/zulip/zulip/commit/62ba8e455d8f460001d9fb486a6dabfd1ed67717Third Party Advisory
- github.com/zulip/zulip/commit/e6eace307ef435eec3395c99247155efed9219e4Third Party Advisory
Other vulnerabilities in zulip
- 9.1 Critical severity
- 7.1 High severity
- 8.2 High severity
- 8.8 High severity
- 9.8 Critical severity
Recent Concurrent Execution using Shared Resource with Improper Synchronization vulnerabilities
- 7.0 High severity
- 7.0 High severity
- 7.0 High severity
- 7.0 High severity
- 7.0 High severity
- 7.0 High severity
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