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CVE-2026-53783— rsync < 3.5.0 TOCTOU Race Condition Directory Escape via rrsync

Quick assessment

Affected
RsyncProject rsync
Exploitation
Public or AI PoC available; prioritize validation
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

RsyncProject Rsync是RsyncProject组织开源的一款速度快、功能极其强大的文件复制工具，可用于复制远程文件和本地文件。 RsyncProject Rsync 3.5.0之前版本存在安全漏洞，该漏洞源于rrsync受限shell包装器中的检查时间到使用时间（TOCTOU）竞争条件，允许经过身份验证的客户端在验证后、传输处理前用符号链接替换路径组件来绕过强制目录限制，还可利用不受限标志读取或写入允许目录子树之外的文件。

CVSS 8.1 · High EPSS 0.37% · P29

Affected Version Matrix 2

VendorProduct Version RangeStatus
RsyncProject rsync ≤ 3.4.4 affected
3.5.0 unaffected
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I. Basic Information for CVE-2026-53783

Vulnerability Information
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Vulnerability Title
rsync < 3.5.0 TOCTOU Race Condition Directory Escape via rrsync
Source: CVE Program / CVE List V5
Vulnerability Description
rsync before 3.5.0 contains a time-of-check to time-of-use (TOCTOU) race condition vulnerability in the rrsync restricted shell wrapper that allows authenticated clients to escape enforced directory restrictions by substituting a symlink for a path component after validation but before transfer processing. Attackers can additionally leverage unrestricted flags such as --copy-unsafe-links, -D, and --log-file through rrsync to read or write files outside the permitted directory subtree.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
在文件访问前对链接解析不恰当(链接跟随)
Source: CVE Program / CVE List V5
Vulnerability Title
RsyncProject Rsync 后置链接漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
RsyncProject Rsync是RsyncProject组织开源的一款速度快、功能极其强大的文件复制工具，可用于复制远程文件和本地文件。 RsyncProject Rsync 3.5.0之前版本存在安全漏洞，该漏洞源于rrsync受限shell包装器中的检查时间到使用时间（TOCTOU）竞争条件，允许经过身份验证的客户端在验证后、传输处理前用符号链接替换路径组件来绕过强制目录限制，还可利用不受限标志读取或写入允许目录子树之外的文件。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
RsyncProject rsync 0 ~ 3.4.4 -

II. Public POCs for CVE-2026-53783

# POC Description Source Link Shenlong Link
AI-Generated POC Premium
Qwen3.6-35B-A3B · 10260 chars
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Vulnerability reproduction recording (real sandbox build + trigger, exclusive)
In-depth vulnerability mechanism
Trigger conditions & impact
Full executable POC code
Exploit chain & mitigation
POC zip download
100+ AI POC generations per month

III. Intelligence Information for CVE-2026-53783

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Vendor Advisories for CVE-2026-53783 (2)

Vendor Pages for CVE-2026-53783 (1)

Same Patch Batch · RsyncProject · 2026-08-13 · 33 CVEs total

CVE-2026-53791 9.1 CRITICAL rsync < 3.5.0 Daemon IP Spoofing via PROXY Protocol Header
CVE-2026-70461 8.2 HIGH rsync 3.2.5 < 3.5.0 Heap Out-of-Bounds Write via files-from Entry
CVE-2026-70456 8.2 HIGH rsync 3.0.1 < 3.5.0 Heap Out-of-Bounds Write via read_args()
CVE-2026-70458 8.2 HIGH rsync 3.0.0 < 3.5.0 Out-of-Bounds Write via FLAG_HLINKED Handling
CVE-2026-70463 8.1 HIGH rsync 3.1.0 < 3.5.0 Authorization Bypass via auth users Directive Parsing
CVE-2026-53790 8.1 HIGH rsync < 3.5.0 Command Injection via Multiple Code Paths
CVE-2026-53795 8.1 HIGH rsync < 3.5.0 Arbitrary File Write via --temp-dir/--link-dest
CVE-2026-70460 8.1 HIGH rsync 2.3.3 < 3.5.0 Path Traversal via --partial-dir/--backup-dir Symlink
CVE-2026-70454 8.0 HIGH rsync < 3.5.0 TLS Certificate Validation Bypass via SSL/OpenSSL Mode
CVE-2026-53803 7.8 HIGH rsync < 3.5.0 Symlink Following Arbitrary File Overwrite
CVE-2026-70455 7.5 HIGH rsync 3.4.2 < 3.5.0 DoS via --zt Zstandard Compression Thread Exhaustion
CVE-2026-70464 7.5 HIGH rsync 2.0.0 < 3.5.0 Connection Slot Exhaustion DoS via Handshake Stall
CVE-2026-70453 7.5 HIGH rsync < 3.5.0 Algorithmic Complexity DoS via hash_search()
CVE-2026-70452 7.4 HIGH rsync 3.1.0 < 3.5.0 Access Control Bypass via DNS Resolution Failure
CVE-2026-53793 7.4 HIGH rsync < 3.5.0 Path Confinement Bypass via /./ Boundary Marker in Chroot Mode
CVE-2026-53802 7.1 HIGH rsync < 3.5.0 Arbitrary File Read via Symlink Following
CVE-2026-53784 7.1 HIGH rsync < 3.5.0 Path Traversal via Symlink Module Root
CVE-2026-53785 7.1 HIGH rsync < 3.5.0 Path Traversal Write Escape via --relative Mode
CVE-2026-53788 6.5 MEDIUM rsync < 3.5.0 Newline Injection via name-converter uid/gid mapping
CVE-2026-53789 6.5 MEDIUM rsync < 3.5.0 Arbitrary File Deletion via Malicious File List

Showing top 20 of 33 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: rsync
Same vendor: RsyncProject
Same weakness: CWE-59

V. Comments for CVE-2026-53783

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