CVE-2026-70457: CWE-131 Incorrect Calculation of Buffer Size in RsyncProject rsync
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.
AI Analysis
Technical Summary
CVE-2026-70457 affects rsync versions 3.2.3 up to and including 3.4.4. The vulnerability is an out-of-bounds write in the parse_size_arg() function where the return value of snprintf() is used directly as an index into a .bss-segment array without verifying that the index is within bounds. When snprintf truncates the formatted size string, its return value reflects the total length that would have been written, which can exceed the array size. This leads to memory corruption in the .bss segment, potentially causing undefined behavior or crashes.
Potential Impact
Successful exploitation of this vulnerability can cause memory corruption in the .bss segment of the rsync process. This may lead to application crashes or other unpredictable behavior. The CVSS 4.0 score is 8.3 (high severity), indicating a significant risk if exploited. There are no known exploits in the wild at this time.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. No official fix or patch information is provided in the available data. Users should monitor the RsyncProject advisories for updates and apply any official patches once released.
CVE-2026-70457: CWE-131 Incorrect Calculation of Buffer Size in RsyncProject rsync
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.
CVSS v4.0
Score 8.3high
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-70457 affects rsync versions 3.2.3 up to and including 3.4.4. The vulnerability is an out-of-bounds write in the parse_size_arg() function where the return value of snprintf() is used directly as an index into a .bss-segment array without verifying that the index is within bounds. When snprintf truncates the formatted size string, its return value reflects the total length that would have been written, which can exceed the array size. This leads to memory corruption in the .bss segment, potentially causing undefined behavior or crashes.
Potential Impact
Successful exploitation of this vulnerability can cause memory corruption in the .bss segment of the rsync process. This may lead to application crashes or other unpredictable behavior. The CVSS 4.0 score is 8.3 (high severity), indicating a significant risk if exploited. There are no known exploits in the wild at this time.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. No official fix or patch information is provided in the available data. Users should monitor the RsyncProject advisories for updates and apply any official patches once released.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- VulnCheck
- Date Reserved
- 2026-08-04T14:52:23.814Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a7ddecabf8831d5395d0066
Added to database: 08/13/2026, 15:12:10 UTC
Last enriched: 08/13/2026, 15:29:12 UTC
Last updated: 08/13/2026, 18:08:52 UTC
Views: 5
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