How severe is CVE-2026-53803?

CVE-2026-53803 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-53803 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (13th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-53803?

CVE-2026-53803 affects Samba Rsync. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-53803?

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

When was CVE-2026-53803 published?

CVE-2026-53803 was published on 2026-08-13 and last updated on 2026-08-31.

CVE-2026-53803

CVE-2026-53803 is a high-severity vulnerability in Samba Rsync with a CVSS 3.x base score of 7.8. 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-59.

Key facts

Severity: High (CVSS 3.x base score 7.8)
CVSS v4: 8.5
EPSS exploit prediction: 0% (13th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-59
Affected product: Samba Rsync
Published: 2026-08-13
Last modified: 2026-08-31

Description

rsync before 3.5.0 contains a symlink following vulnerability that allows local attackers to overwrite arbitrary files by placing a symlink at a predictable output path such as --log-file, --write-batch, or daemon-mode log and statistics paths. Attackers can exploit rsync's failure to reject symlinks during ancillary file writes to redirect output to arbitrary filesystem locations, achieving local privilege escalation on installations where rsync runs with elevated privileges such as setuid or privileged daemon configurations.

Frequently asked questions

What is CVE-2026-53803?: rsync before 3.5.0 contains a symlink following vulnerability that allows local attackers to overwrite arbitrary files by placing a symlink at a predictable output path such as --log-file, --write-batch, or daemon-mode log and statistics paths. Attackers can exploit rsync's failure to reject symlinks during ancillary file writes to redirect output to arbitrary filesystem locations, achieving local privilege escalation on installations where rsync runs with elevated privileges such as setuid or privileged daemon configurations.
How severe is CVE-2026-53803?: CVE-2026-53803 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-53803 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (13th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-53803?: CVE-2026-53803 affects Samba Rsync. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-53803?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2026-53803 published?: CVE-2026-53803 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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