What’s Vulnerable › Vulnerabilities

CVE-2026-70457: rsync 3.2.3 < 3.5.0 Out-of-Bounds Write via parse_size_arg()

• Severity: high (CVSS 8.2 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-13 · updated 2026-10-24
• Weakness: CWE-131

Description

rsync 3.2.3 before 3.5.0 contains an out-of-bounds write in parse_size_arg() where the return value of snprintf() is used directly as an index into a .bss-segment array without bounds checking. When snprintf truncates the formatted size string, the return value equals the number of characters that would have been written including the truncated portion, and this value may exceed the array length. The subsequent indexed write targets memory outside the intended array bounds, corrupting .bss memory.

Affected products

• RsyncProject rsync: from 3.2.3 before 3.5.0 — fixed in 3.5.0

How to fix

Upgrade to a fixed version: RsyncProject rsync 3.5.0. Check the vendor advisory for mitigations.

References

• https://github.com/RsyncProject/rsync/releases/tag/v3.5.0
• https://github.com/RsyncProject/rsync/security/advisories/GHSA-pg7g-xqmr-xpfh
• https://www.vulncheck.com/advisories/rsync-out-of-bounds-write-via-parse-size-arg

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