CVE-2026-43618

Description

Rsync version 3.4.2 and prior contain an integer overflow vulnerability in the compressed-token decoder where a 32-bit signed counter is not checked for overflow, allowing a malicious sender to trigger an overflow that causes the receiver process to read and return data from outside the intended buffer bounds. Attackers can exploit this vulnerability to disclose process memory contents including environment variables, passwords, heap and stack data, and library memory pointers, significantly reducing ASLR effectiveness and facilitating further exploitation.

Overview

State: PUBLISHED
Assigner (CNA): VulnCheck
CVSS severity: MEDIUM
CVSS score: 6.1 / 10
CVSS vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:H/SC:N/SI:N/SA:N
Effective score: 6.1 / 10 MEDIUM source: CNA overview
MSRC score: 8.1 / 10 HIGH MS rating: Important
CWE(s): CWE-190, CWE-125
Reserved: 2026-05-01
Published: 2026-05-20 00:50 UTC
Last updated: 2026-05-20 13:04 UTC
Source: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/43xxx/CVE-2026-43618.json
Linked Threat: CVE-2026-43618 — CVE-2026-43618

NVD triage scoring NVD CVE 2.0

Layer NVD adds on top of the CNA's CVE record — published / last-modified timestamps, exploitability / impact subscores, and the FIRST.org EPSS probability that this CVE will be exploited in the wild in the next 30 days.

NVD published: 2026-05-20 02:16:36 UTC
NVD last modified: 2026-05-21 20:34:38 UTC
NVD CVSS v3.1: 8.1 / 10 HIGH source: disclosure@vulncheck.com
NVD CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Exploitability subscore: 2.8 / 10
Impact subscore: 5.2 / 10
EPSS score: 0.0005 (probability of exploitation in next 30 days)
EPSS percentile: 15.79% vs all CVEs — higher = more likely to be exploited, as of 2026-05-24

European Union Vulnerability Database ENISA EUVD

ENISA's official EU repository for curated vulnerability intelligence. Carries a separate identifier (EUVD-YYYY-NNNN) and frequently exposes an earlier-published description + CVSS than NVD does.

EUVD ID: EUVD-2026-31011
Assigner: VulnCheck
Published: May 20, 2026, 12:50:21 AM
Updated: May 20, 2026, 1:04:03 PM
EUVD base score (CVSS 4.0): 6.1 / 10
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:H/SC:N/SI:N/SA:N
EUVD-reported EPSS: 0.0600
Vendors: RsyncProject
Products: rsync (0 <3.4.3)
Aliases: GHSA-88m5-cm5m-2596

ENISA description: Rsync version 3.4.2 and prior contain an integer overflow vulnerability in the compressed-token decoder where a 32-bit signed counter is not checked for overflow, allowing a malicious sender to trigger an overflow that causes the receiver process to read and return data from outside the intended buffer bounds. Attackers can exploit this vulnerability to disclose process memory contents including environment variables, passwords, heap and stack data, and library memory pointers, significantly reducing ASLR effectiveness and facilitating further exploitation.

EUVD references (3)

Microsoft Security Response Center MSRC

Microsoft's vendor-authoritative record from the Security Update Guide — its own CVSS score, impact, severity rating, exploit assessment, and KB-article fixes. Refreshed 2026-07-28 03:00 UTC (source: CVRF).

MS severity: Important
MS CVSS base score: 8.1 / 10 (temporal 8.1)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Release: 2026-May

Microsoft remediations / KB articles (2)

CBL-Mariner Releases — Vendor Fix / Security Update (fixed build 3.4.3-1)
https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade — None Available / CBL-Mariner Releases

Affected products (1)

Vendor	Product	Versions	Platforms
RsyncProject	rsync	`0` (affected)	—

Affected products — CPE 2.3 (1) NVD

NVD's normalized CPE 2.3 matchers, used by vendor tools (vulnerability scanners, asset managers) for automated detection. Compare with the CNA's free-text "Affected products" section above.

cpe:2.3:a:samba:rsync:*:*:*:*:*:*:*:*

Vendor references (3)

References embedded in the original CVE record by the assigning CNA.

https://github.com/RsyncProject/rsync/security/advisories/GHSA-g37v-g3gj-pmwq vendor-advisory
https://github.com/RsyncProject/rsync/releases/tag/v3.4.3 release-notes
https://www.vulncheck.com/advisories/rsync-integer-overflow-information-disclosure third-party-advisory

Web references (8)

DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.

None Available msrc
MSRC update guide: CVE-2026-43618 msrc
https://nvd.nist.gov/vuln/detail/CVE-2026-43618 tenable:nvd.nist.gov
https://www.cve.org/CVERecord?id=CVE-2026-43618 tenable:www.cve.org
https://www.first.org/epss/ tenable:www.first.org
https://github.com/RsyncProject/rsync/releases/tag/v3.4.3 tenable:github.com
https://www.vulncheck.com/advisories/rsync-integer-overflow-information-disclosure tenable:www.vulncheck.com
https://github.com/RsyncProject/rsync/security/advisories/GHSA-g37v-g3gj-pmwq tenable:github.com

NVD-tagged references (3)

Reference list NVD curates from the CNA record, vendor advisories, and third-party reports. The tag chips below are NVD's analyst-assigned categories.

https://github.com/RsyncProject/rsync/releases/tag/v3.4.3 disclosure@vulncheck.com Release Notes
https://github.com/RsyncProject/rsync/security/advisories/GHSA-g37v-g3gj-pmwq disclosure@vulncheck.com Vendor Advisory
https://www.vulncheck.com/advisories/rsync-integer-overflow-information-disclosure disclosure@vulncheck.com Third Party Advisory

Remediations (15)

Remediations are stored against the linked Threat row; the list below is deduplicated across both pages.

CISA Warns of Exploited Microsoft Defender 0-Day Flaws

web:cyberpress.org

The U.S. Cybersecurity and Infrastructure Security Agency (CISA) has added two actively exploited Microsoft Defender vulnerabilities to its Known Exploited Vulnerabilities (KEV) catalog, issuing an urgent remediation directive for federal agencies with a due date of June 3, 2026 .

2026-05-23 22:17 UTC
Microsoft Patch Tuesday March 2026 - 78 Vulnerabilities Fixed ...

web:cybersecuritynews.com

Microsoft released its March 2026 Patch Tuesday security update on March 10, 2026 , addressing 78 vulnerabilities across Windows, Microsoft Office, Azure, SQL Server, and .NET. The update includes one actively exploited zero-day vulnerability and multiple Critical-rated flaws demanding immediate attention from security teams. The most urgent fix this month is CVE - 2026 -21262, the sole zero-day ...

2026-05-23 22:17 UTC
Six Patch Management Best Practices [Updated 2026]

web:heimdalsecurity.com

Explore six essential patch management best practices for 2026 to keep your systems secure, up to date, and protected from vulnerabilities.

2026-05-23 22:17 UTC
Patch Tuesday, May 2026 Edition - Krebs on Security

web:krebsonsecurity.com

Microsoft expects that exploitation is more likely. May's Patch Tuesday is a welcome respite from April, which saw Microsoft fix a near-record 167 security flaws.

2026-05-23 22:17 UTC
Nvd - Cve-2026-43618

web:nvd.nist.gov

An official website of the United States government Here's how you know

2026-05-23 22:17 UTC
Security Update Guide - Microsoft

web:portal.msrc.microsoft.com

The Security Update Guide provides information on the latest Microsoft security updates, helping users understand and address potential vulnerabilities effectively.

2026-05-23 22:17 UTC
Google Translate

web:translate.google.com

Google's service, offered free of charge, instantly translates words, phrases, and web pages between English and over 100 other languages.

2026-05-23 22:17 UTC
Oracle Critical Patch Update Advisory - April 2026

web:www.oracle.com

This Critical Patch Update contains 481 new security patches across the product families listed below. Please note that an MOS note summarizing the content of this Critical Patch Update and other Oracle Software Security Assurance activities is located at April 2026 Critical Patch Update: Executive Summary and Analysis.

2026-05-23 22:17 UTC
CVE-2026-43618: Rsync version 3.4.2 and prior Vulnerability

web:www.sherlockforensics.com

Rsync version 3.4.2 and prior vulnerability ( CVE-2026-43618 ) scores CVSS 8.1 HIGH. Analysis of affected systems and remediation steps.

2026-05-23 22:17 UTC
Patch Tuesday May 2026: Security Updates & CVE Analysis

web:zecurit.com

Get the complete breakdown of Microsoft's May 2026 Patch Tuesday. We analyze the latest security updates and all critical CVEs .

2026-05-23 22:17 UTC
Windows Kerberos RC4 deprecation: what will break in Active ... - 4sysops

web:4sysops.com

Starting in April 2026 , Windows updates will change the default Kerberos ticket issuance behavior to AES-SHA1 for accounts without explicit encryption settings, while RC4 can still be used where explicitly enabled. This change, driven by CVE - 2026 -20833, affects every Windows Server environment where service accounts or devices still rely on RC4. Any service account, NAS device, or legacy ...

2026-05-26 02:58 UTC
Security Advisory Bulletin 064 | Ubiquiti Community

web:community.ui.com

Published: May 21, 2026 Updated: May 22, 2026 Version: 1.1 Revision: 1.1 Summary 1 of 5 A malicious actor with access to the network and high privileges could exploit an Improper Input Validation vulnerability found in UniFi OS devices to execute a Command Injection. Affected Products: UniFi OS Server (Version 5.0.6 and earlier) Mitigation : Update your UniFi OS Server to Version 5.0.8 or later ...

2026-05-26 02:58 UTC
Patch Tuesday, April 2026 Edition - Krebs on Security

web:krebsonsecurity.com

For a clickable, per- patch breakdown, check out the SANS Internet Storm Center Patch Tuesday roundup. Running into problems applying any of these updates?

2026-05-26 02:58 UTC
March 23, 2026—Hotpatch KB5085518 (OS Builds 26200.7985 and 26100.7985 ...

web:support.microsoft.com

This out-of-band update for Windows 11, version 25H2 and 24H2 (KB5085518) includes fixes and improvements. To learn more about differences between security updates, optional non-security preview updates, out-of-band (OOB) updates, and continuous innovation, see Windows monthly updates explained. For information on Windows update terminology, see the different types of Windows software updates ...

2026-05-26 02:58 UTC
Microsoft Patches 138 Vulnerabilities, Including DNS and Netlogon RCE Flaws

web:thehackernews.com

Microsoft patched 138 flaws, including 30 Critical bugs, as AI discovery expands Patch Tuesday risk.

2026-05-26 02:58 UTC

AI Forensic Analysis

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Raw JSON

The full cvelistV5 record. Download as CVE-2026-43618.json.

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