Rsync < 3.4.3 Off-by-One Stack Write via HTTP Proxy

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Summary

CVECVE-2026-45232
StatePUBLISHED
AssignerVulnCheck
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-05-20 02:16:36 UTC
Updated2026-05-21 20:52:56 UTC
DescriptionRsync versions before 3.4.3 contain an off-by-one out-of-bounds stack write vulnerability in the establish_proxy_connection() function in socket.c that allows network attackers to corrupt stack memory by sending a malformed HTTP proxy response. Attackers can exploit this by positioning themselves between the client and proxy or controlling the proxy server to send a response line of 1023 or more bytes without a newline terminator, causing a null byte to be written to an out-of-bounds stack address when the RSYNC_PROXY environment variable is set.

Risk And Classification

Primary CVSS: v4.0 2.1 LOW from [email protected]

CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS: 0.000430000 probability, percentile 0.132090000 (date 2026-05-27)

Problem Types: CWE-193 | CWE-193 Off-by-one Error

VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary2.1LOWCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/C...
4.0CNACVSS2.1LOWCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
3.1[email protected]Primary3.7LOWCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
3.1[email protected]Secondary3.1LOWCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:L
3.1CNACVSS3.1LOWCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:L

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
High
Attack Requirements
None
Privileges Required
None
User Interaction
Active
Confidentiality
None
Integrity
None
Availability
Low
Sub Conf.
None
Sub Integrity
None
Sub Availability
None

CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
Low

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

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Samba Rsync All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA RsyncProject Rsync affected 3.4.3 semver Not specified

References

ReferenceSourceLinkTags
github.com/RsyncProject/rsync/releases/tag/v3.4.3 [email protected] github.com Release Notes
github.com/RsyncProject/rsync/security/advisories/GHSA-8f85-j2cv-59m8 [email protected] github.com Vendor Advisory
www.vulncheck.com/advisories/rsync-off-by-one-stack-write-via-http-proxy [email protected] www.vulncheck.com Third Party Advisory
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Michal Ruprich (en)

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