CVE-2026-58270 (CVSS 6.5)

Description

Sync-in Server is an open-source platform for file storage, sharing, collaboration, and syncing. Prior to version 2.4.0, the sync diff endpoint compiles a user-supplied string into a `RegExp` with no complexity validation. A catastrophic-backtracking pattern (e.g. `^(a+)+b`) blocks the Node.js event loop, making the entire server unresponsive to all users until the container is restarted. Version 2.4.0 patches the issue.

Is your site exposed to CVE-2026-58270?

Run a free security scan — no signup, results in seconds.

CVSS v3.1 Score

6.5

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS — Exploit Prediction

0.0035

Probability of exploitation

0.26%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-1333 CWE-1333

References

Other References

https://github.com/Sync-in/server/security/advisories/GHSA-jx63-h26r-8cph https://github.com/Sync-in/server/security/advisories/GHSA-jx63-h26r-8cph

Frequently Asked Questions

What is CVE-2026-58270? +

Sync-in Server is an open-source platform for file storage, sharing, collaboration, and syncing. Prior to version 2.4.0, the sync diff endpoint compiles a user-supplied string into a `RegExp` with no complexity validation. A catastrophic-backtracking pattern (e.g. `^(a+)+b`) blocks the Node.js event loop, making the entire server unresponsive to all users until the container is restarted. Version 2.4.0 patches the issue. It has a CVSS v3.1 base score of 6.5 (MEDIUM).

How severe is CVE-2026-58270? +

CVE-2026-58270 has a CVSS v3.1 score of 6.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0035, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-58270? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2026-45409

Internationalized Domain Names in Applications (IDNA) for Python provides support for Internationalized Domain Names in Applications (IDNA) and Unicode IDNA …

CVE-2025-48058

PowSyBl (Power System Blocks) is a framework to build power system oriented software. Prior to version 6.7.2, there is a …

CVE-2025-48059

PowSyBl (Power System Blocks) is a framework to build power system oriented software. In com.powsybl:powsybl-iidm-criteria versions 6.3.0 to before 6.7.2 …

CVE-2025-6998

ReDoS in strip_whitespaces() function in cps/string_helper.py in Calibre Web and Autocaliweb allows unauthenticated remote attackers to cause denial of service …

CVE-2025-54363

Microsoft Knack 0.12.0 allows Regular expression Denial of Service (ReDoS) in the knack.introspection module. extract_full_summary_from_signature employs an inefficient regular expression …

CVE-2025-54364

Microsoft Knack 0.12.0 allows Regular expression Denial of Service (ReDoS) in the knack.introspection module. option_descriptions employs an inefficient regular expression …

CVE-2026-58270