How severe is CVE-2026-53791?

CVE-2026-53791 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 high, and availability none.

Is CVE-2026-53791 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-53791?

CVE-2026-53791 affects Samba Rsync. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-53791?

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-2026-53791 published?

CVE-2026-53791 was published on 2026-08-13 and last updated on 2026-08-31.

CVE-2026-53791

CVE-2026-53791 is a critical-severity vulnerability in Samba Rsync 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-290.

Key facts

Severity: Critical (CVSS 3.x base score 9.1)
CVSS v4: 9.1
EPSS exploit prediction: 1% (42nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-290
Affected product: Samba Rsync
Published: 2026-08-13
Last modified: 2026-08-31

Description

rsync daemon before 3.5.0 contains an IP address spoofing vulnerability that allows unauthenticated remote attackers to bypass IP-based access controls by sending a crafted PROXY protocol header with a forged source address. Attackers who can connect directly to the rsync daemon can inject a spoofed source IP in the PROXY protocol header to circumvent hosts allow/deny rules, gaining unauthorized access that would otherwise be blocked based on their real source address.

Frequently asked questions

What is CVE-2026-53791?: rsync daemon before 3.5.0 contains an IP address spoofing vulnerability that allows unauthenticated remote attackers to bypass IP-based access controls by sending a crafted PROXY protocol header with a forged source address. Attackers who can connect directly to the rsync daemon can inject a spoofed source IP in the PROXY protocol header to circumvent hosts allow/deny rules, gaining unauthorized access that would otherwise be blocked based on their real source address.
How severe is CVE-2026-53791?: CVE-2026-53791 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 high, and availability none.
Is CVE-2026-53791 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-53791?: CVE-2026-53791 affects Samba Rsync. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-53791?: 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-2026-53791 published?: CVE-2026-53791 was published on 2026-08-13 and last updated on 2026-08-31.

References

Affected products (1)

cpe:2.3:a:samba:rsync:*:*:*:*:*:*:*:*

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