The vulnerability CVE-2023-22735 could compromise system integrity but typically requires user interaction to be exploited.
Status: Modified
Last updated: 🕢 21 Nov 2024, 07:45 UTC
Originally published on: 🕖 07 Feb 2023, 19:15 UTC
Time between publication and last update: 652 days
CVSS Release: version 3
security-advisories@github.com
Secondary
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:N
CVE-2023-22735: Zulip is an open-source team collaboration tool. In versions of zulip prior to commit `2f6c5a8` but after commit `04cf68b` users could upload files with arbitrary `Content-Type` which would be served from the Zulip hostname with `Content-Disposition: inline` and no `Content-Security-Policy` header, allowing them to trick other users into executing arbitrary Javascript in the context of the Zulip application. Among other things, this enables session theft. Only deployments which use the S3 storage (not the local-disk storage) are affected, and only deployments which deployed commit 04cf68b45ebb5c03247a0d6453e35ffc175d55da, which has only been in `main`, not any numbered release. Users affected should upgrade from main again to deploy this fix. Switching from S3 storage to the local-disk storage would nominally mitigate this, but is likely more involved than upgrading to the latest `main` which addresses the issue.
The exploitability of CVE-2023-22735 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).
This vulnerability, CVE-2023-22735, requires a high level of attack complexity and low privileges, making it difficult but not impossible to exploit. Organizations should ensure robust security configurations to mitigate risks.
A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.
Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.
Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.
Above is the CVSS Sub-score Breakdown for CVE-2023-22735, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.
Below is the Impact Analysis for CVE-2023-22735, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.
The EPSS score estimates the probability that this vulnerability will be exploited in the near future.
EPSS Score: 0.118% (probability of exploit)
EPSS Percentile: 47.42%
(lower percentile = lower relative risk)
This vulnerability is less risky than approximately 52.58% of others.
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