How severe is CVE-2023-43644?

CVE-2023-43644 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability high.

Is CVE-2023-43644 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (48th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2023-43644?

CVE-2023-43644 primarily affects Sagernet Sing-box. In total, 16 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2023-43644?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2023-43644 published?

CVE-2023-43644 was published on 2023-09-25 and last updated on 2026-06-17.

CVE-2023-43644

CVE-2023-43644 is a critical-severity vulnerability in Sagernet Sing-box with a CVSS 3.x base score of 9.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-306.

Key facts

Severity: Critical (CVSS 3.x base score 9.1)
EPSS exploit prediction: 1% (48th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-306
Affected product: Sagernet Sing-box
Published: 2023-09-25
Last modified: 2026-06-17

Description

Sing-box is an open source proxy system. Affected versions are subject to an authentication bypass when specially crafted requests are sent to sing-box. This affects all SOCKS5 inbounds with user authentication and an attacker may be able to bypass authentication. Users are advised to update to sing-box 1.4.4 or to 1.5.0-rc.4. Users unable to update should not expose the SOCKS5 inbound to insecure environments.

Frequently asked questions

What is CVE-2023-43644?: Sing-box is an open source proxy system. Affected versions are subject to an authentication bypass when specially crafted requests are sent to sing-box. This affects all SOCKS5 inbounds with user authentication and an attacker may be able to bypass authentication. Users are advised to update to sing-box 1.4.4 or to 1.5.0-rc.4. Users unable to update should not expose the SOCKS5 inbound to insecure environments.
How severe is CVE-2023-43644?: CVE-2023-43644 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability high.
Is CVE-2023-43644 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (48th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2023-43644?: CVE-2023-43644 primarily affects Sagernet Sing-box. In total, 16 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2023-43644?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2023-43644 published?: CVE-2023-43644 was published on 2023-09-25 and last updated on 2026-06-17.

References

https://github.com/SagerNet/sing-box/security/advisories/GHSA-r5hm-mp3j-285g

Affected products (16)

cpe:2.3:a:sagernet:sing-box:*:*:*:*:*:*:*:*
cpe:2.3:a:sagernet:sing-box:1.5.0:beta1:*:*:*:*:*:*
cpe:2.3:a:sagernet:sing-box:1.5.0:beta10:*:*:*:*:*:*
cpe:2.3:a:sagernet:sing-box:1.5.0:beta11:*:*:*:*:*:*
cpe:2.3:a:sagernet:sing-box:1.5.0:beta12:*:*:*:*:*:*
cpe:2.3:a:sagernet:sing-box:1.5.0:beta2:*:*:*:*:*:*
cpe:2.3:a:sagernet:sing-box:1.5.0:beta3:*:*:*:*:*:*
cpe:2.3:a:sagernet:sing-box:1.5.0:beta4:*:*:*:*:*:*
cpe:2.3:a:sagernet:sing-box:1.5.0:beta5:*:*:*:*:*:*
cpe:2.3:a:sagernet:sing-box:1.5.0:beta6:*:*:*:*:*:*
cpe:2.3:a:sagernet:sing-box:1.5.0:beta7:*:*:*:*:*:*
cpe:2.3:a:sagernet:sing-box:1.5.0:beta8:*:*:*:*:*:*
cpe:2.3:a:sagernet:sing-box:1.5.0:beta9:*:*:*:*:*:*
cpe:2.3:a:sagernet:sing-box:1.5.0:rc1:*:*:*:*:*:*
cpe:2.3:a:sagernet:sing-box:1.5.0:rc2:*:*:*:*:*:*
cpe:2.3:a:sagernet:sing-box:1.5.0:rc3:*:*:*:*:*:*

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