CVE-2026-119741— rsync through 3.5.1 Denial of Service via hash_search() Checksum Collisions

Quick assessment

Affected

RsyncProject rsync

Exploitation

No confirmed in-the-wild exploitation; assess based on exposure

Recommended action

Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

rsync 3.5.1 及更早版本存在一个拒绝服务漏洞，该漏洞位于文件中 delta-transfer 发送端的函数。恶意接收方可利用此漏洞，在连续偏移量处触发无限制的强校验和计算。未认证的攻击者从公共守护进程模块拉取数据时，可提交与连续滚动窗口发生碰撞的弱校验和，并搭配不匹配的强校验和，从而在多并发连接下耗尽发送端的 CPU 资源。

CVSS 7.5 · High Updated Nov 04, 2026

Possible ATT&CK Techniques 1 AI

T1499 · Endpoint Denial of Service

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Vulnerability Information

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Vulnerability Title

rsync through 3.5.1 Denial of Service via hash_search() Checksum Collisions

Source: CVE Program / CVE List V5

Vulnerability Description

rsync through 3.5.1 contains a denial of service vulnerability in the delta-transfer sender's hash_search() in match.c that allows malicious receivers to trigger unbounded strong-checksum work at consecutive offsets. Unauthenticated attackers pulling from a public daemon module can supply weak checksums colliding with consecutive rolling windows plus non-matching strong checksums, exhausting sender CPU across concurrent connections.

Source: CVE Program / CVE List V5

CVSS Information

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Source: CVE Program / CVE List V5

Vulnerability Type

算法复杂性

Source: CVE Program / CVE List V5

Affected Products

Vendor	Product	Affected Versions	CPE	Subscribe
RsyncProject	rsync	0 ~ 3.5.1	-

II. Public POCs for CVE-2026-119741

#	POC Description	Source Link	Shenlong Link

AI-Generated POC Premium

No public POC found.

III. Intelligence Information for CVE-2026-119741

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Other References for CVE-2026-119741 (5)

https://github.com/RsyncProject/rsync product
https://github.com/RsyncProject/rsync/blob/a7404a9a633cff28ee1602f328b9c3fa69cdbd04/testsuite/hashsearch-collision-skip_test.py technical-description
https://github.com/RsyncProject/rsync/commit/a7404a9a633cff28ee1602f328b9c3fa69cdbd04 patch
https://github.com/RsyncProject/rsync/pull/1132 issue-tracking patch
https://www.vulncheck.com/advisories/rsync-through-3.5.1-denial-of-service-via-hash-search-checksum-collisions third-party-advisory

https://www.cve.org/CVERecord?id=CVE-2026-119741

IV. Related Vulnerabilities

Same product: rsync

Same vendor: RsyncProject

Same weakness: CWE-407