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NVD / CVE Program· CNA VulnCheck

CVE-2026-43620: Rsync < 3.4.3 Out-of-Bounds Array Read via recv_files()

Noroxi assessment

Priority: Monitor (action score 27/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.42% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No special conditions are required; it is repeatable.
  • Fixed version: RsyncProject rsync 3.4.3; azl3 rsync 3.4.1-2 on Azure Linux 3.0 3.4.3-1.

Low priority for now. Upgrade to RsyncProject rsync 3.4.3; azl3 rsync 3.4.1-2 on Azure Linux 3.0 3.4.3-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

Rsync version 3.4.2 and prior contain a receiver-side out-of-bounds array read vulnerability in recv_files() in receiver.c that allows a malicious rsync server to crash the rsync client process. Attackers can exploit the vulnerability by setting CF_INC_RECURSE in compatibility flags and sending a specially crafted file list where the first sorted entry is not the leading dot directory, followed by a transfer record with ndx=0 and an iflag word without ITEM_TRANSFER, causing the receiver to read 8 bytes before the allocated pointer array and dereference an invalid pointer at an unmapped address, resulting in a deterministic SIGSEGV crash of the rsync client.

MediumCVSS 6.9 · v4.0—No exploit Fix available
Published
May 19, 2026
Updated
Nov 8, 2026
EPSS
0.4% · 37th percentile

Report tools

JSON

Action score

27

Monitor

Low priority for now.

CVSS
27 / 40 · 6.9 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.4%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · VulnCheck
6.9
NVD has not scored this yet; the score shown is the CNA’s.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-43620

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
sambarsync

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • samba rsyncup to 3.4.2 inclusive

Versions reported by the vendor

Affected version ranges reported by the assigning authority (VulnCheck). Independent of NVD's CPE analysis and usually ahead of it.

  • RsyncProject rsync

    • before 3.4.3affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Alpine:v3.20rsyncbefore 3.4.3-r03.4.3-r0
Debian:12rsyncbefore 3.2.7-1+deb12u53.2.7-1+deb12u5
Debian:13rsyncbefore 3.4.1+ds1-5+deb13u33.4.1+ds1-5+deb13u3
Debian:14rsyncbefore 3.4.3+ds1-13.4.3+ds1-1
openSUSE:Leap 16.0rsyncbefore 3.4.1-160000.6.13.4.1-160000.6.1
openSUSE:Tumbleweedrsyncbefore 3.4.3-1.13.4.3-1.1
SUSE:Linux Enterprise Server 16.0rsyncbefore 3.4.1-160000.4.13.4.1-160000.4.1
SUSE:Linux Micro 6.0rsyncbefore 3.2.7-8.13.2.7-8.1
SUSE:Linux Micro 6.2rsyncbefore 3.4.1-160000.6.13.4.1-160000.6.1

Same product

samba: all records

Other highest-scoring records for the same primary product.

  • CVE-2024-12084Rsync: heap buffer overflow in rsync due to improper checksum length handling
    61This week
  • CVE-2017-16548The receive_xattr function in xattrs.c in rsync 3.1.2 and 3.1.3-development does not check for a trailing '\0' character in an xattr name, w
    41Plan
  • CVE-2017-17434The daemon in rsync 3.1.2, and 3.1.3-development before 2017-12-03, does not check for fnamecmp filenames in the daemon_filter_list data str
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-43618May 19, 2026 · Rsync < 3.4.3 Integer Overflow Information Disclosure
    24Monitor
  • ← EarlierCVE-2026-43619May 19, 2026 · Rsync < 3.4.3 Symlink Race Condition via Path-Based Syscalls
    28Monitor
  • Later →CVE-2026-45232May 19, 2026 · Rsync < 3.4.3 Off-by-One Stack Write via HTTP Proxy
    8Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
RsyncProject rsync3.4.3Vendor (CNA)
azl3 rsync 3.4.1-2 on Azure Linux 3.03.4.3-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
alpine:rsync3.4.3-r0 · Alpine:v3.20Package registry (OSV)
debian:rsync3.2.7-1+deb12u5 · Debian:12Package registry (OSV)
opensuse:rsync3.4.3-1.1 · openSUSE:TumbleweedPackage registry (OSV)
suse:rsync3.4.1-160000.4.1 · SUSE:Linux Enterprise Server 16.0Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-436180 days apartRsync < 3.4.3 Integer Overflow Information Disclosure
    24Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
Integrity
Availability
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
A
Scope
X

Weakness class (CWE)

CWE-125 · Out-of-bounds Read

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

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References

Show all references (2 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records