Evidence used
- No CISA KEV confirmation is currently recorded.
- EPSS is 0.46% for the current model date.
BlackTreeCVE IntelligenceFull vulnerability report · 2026
CVE-2026-43620High confidence
Rsync < 3.4.3 Out-of-Bounds Array Read via recv_files()
RsyncProject · rsync
Official source article: GitHub GHSA-28PW-R563-RXVM ↗. Check the applicable product and release in the original source.
6.9MediumCVSS 4.0
Patch only the product branches with a verified fix
Fix availability varies by productMedium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority. Verified remediation exists for at least one product or source, but 17 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.
R
Open reassessment dashboard →Operational reassessment
Published severity in operational context
Published severityMedium→Operational priority:Medium, unchanged from published severity.unchanged
Compensating controls
- Apply the linked authoritative mitigation while planning the permanent fix.
- Restrict the affected network interface to trusted sources where business-safe.
- Monitor vendor guidance and exploitation sources for a material change.
Verification
- Confirm that the asset runs RsyncProject rsync and falls inside the recorded affected range.
- Recheck the vendor advisory before scheduling a change because no verified fixed version is currently retained.
- Validate exposure, authentication requirements and compensating controls in the actual environment.
- Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Remediation availability differs by product scope
Verified remediation exists for at least one product or source, but 17 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.
- Red Hat Product Security: 17 affected or under-investigation product states without a fixed product state in the same current advisory
Distribution package intelligence
8 package statesRelease-specific package status
Alpine, Debian, ubuntu findings are scoped to the named distribution, release and source package. An absent finding does not mean a package is unaffected.
Repository candidate not checked
A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.
| Distribution release | Source package | Vendor state | Fixed version | Evidence |
|---|---|---|---|---|
| Alpine v3.23v3.23 · main | rsync | Vendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected. | 3.4.3-r0 | Alpine Security Database ↗Source updated 3 Oct 2026 |
| Alpine v3.22v3.22 · main | rsync | Vendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected. | 3.4.3-r0 | Alpine Security Database ↗Source updated 3 Oct 2026 |
| Alpine v3.21v3.21 · main | rsync | Vendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected. | 3.4.3-r0 | Alpine Security Database ↗Source updated 3 Oct 2026 |
| Debian trixietrixie · source | rsync | Vendor fix publishedDebian records a fixed source-package version for this release. | 3.4.1+ds1-5+deb13u3 | Debian Security Tracker ↗Source updated 5 Oct 2026 |
| Debian bookwormbookworm · source | rsync | Vendor fix publishedDebian records a fixed source-package version for this release. | 3.2.7-1+deb12u5 | Debian Security Tracker ↗Source updated 5 Oct 2026 |
| Debian forkyforky · source | rsync | Vendor fix publishedDebian records a fixed source-package version for this release. | 3.4.3+ds1-1 | Debian Security Tracker ↗Source updated 5 Oct 2026 |
| Debian sidsid · source | rsync | Vendor fix publishedDebian records a fixed source-package version for this release. | 3.4.3+ds1-1 | Debian Security Tracker ↗Source updated 5 Oct 2026 |
| Ubuntu 24.04 LTSnoble · standard archive | rsync | Vendor fix publishedCanonical reports that a fixed source package version has been published. Repository candidate availability is not checked by BlackTree. | 3.2.7-1ubuntu1.4 | Canonical Ubuntu Security ↗Source updated 5 Oct 2026 |
Direct vendor intelligence
1 currentAuthoritative vendor CSAF and VEX advisories
Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.
CVE-2026-43620 · CSAF 2.0 · revision 3 · finalRed Hat Product Securityrsync: rsync: Remote Denial of Service via Out-of-bounds Read
The vendor explicitly identifies these products as affected by this CVE.
- rsync as a component of Red Hat Enterprise Linux 10
- rsync-daemon as a component of Red Hat Enterprise Linux 10
- rsync-rrsync as a component of Red Hat Enterprise Linux 10
- rsync.src as a component of Red Hat Enterprise Linux 10
- rsync as a component of Red Hat Enterprise Linux 6
- rsync.src as a component of Red Hat Enterprise Linux 6
- rsync as a component of Red Hat Enterprise Linux 7
- rsync.src as a component of Red Hat Enterprise Linux 7
- rsync as a component of Red Hat Enterprise Linux 8
- rsync-daemon as a component of Red Hat Enterprise Linux 8
- rsync.src as a component of Red Hat Enterprise Linux 8
- rsync as a component of Red Hat Enterprise Linux 9
- Summary
- A flaw was found in rsync. A malicious rsync server can exploit an out-of-bounds read vulnerability in the `recv_files()` function. By manipulating compatibility flags and transfer records, the server can cause a connecting client to attempt to read memory outside of allocated bounds. This can lead to a segmentation fault, resulting in a denial of service for the client.
- Remediation
- To mitigate this issue, rsync clients can be configured to disable incremental recursion when pulling from untrusted sources. This can be achieved by using the `--no-inc-recursive` option. Example: `rsync --no-inc-recursive [OPTIONS] SOURCE DESTINATION` Disabling incremental recursion may affect the efficiency of transfers for large, frequently updated directories.
Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority. Verified remediation exists for at least one product or source, but 17 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.
Fix availability varies by product01
What, why and how
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.
What
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.
Why
The product reads data past the end, or before the beginning, of the intended buffer.
How
An attacker operating through a network path may attempt exploitation when the stated preconditions are met. If successful, the issue may disrupt the affected service.
What
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.
Why
The product reads data past the end, or before the beginning, of the intended buffer.
How
An attacker operating through a network path may attempt exploitation when the stated preconditions are met. If successful, the issue may disrupt the affected service.
02
Exploit reality and attack path
CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.
Observed exploitation No confirmed evidence
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.
Public PoC / exploit material None recorded
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.
- Likely attack path
- a network path → Out-of-bounds Read → disrupt the affected service
- Attack surface
- Network
- Privileges required
- None: unauthenticated exploitation is possible
- User interaction
- Active interaction required
- Attack complexity
- Low: no specialised conditions are recorded
- Security boundary
- Not a CVSS 4.0 base metric
- Weakness
?
CWE means Common Weakness Enumeration: a standard category for the underlying weakness. - CWE-125 ↗
CWE-125: Out-of-bounds Read. The product reads data past the end, or before the beginning, of the intended buffer.
- CVSS vector
?
CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity. CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:NCommon Vulnerability Scoring System 4.0: the compact vector below is decoded into plain language.
AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.ATNoneAttack requirements: No additional deployment or execution condition is required.PRNonePrivileges required: The attacker does not need an account or existing privileges.UIActiveUser interaction: A user must take a deliberate action for exploitation to succeed.VCNoneVulnerable-system confidentiality: No direct loss is represented by this metric.VINoneVulnerable-system integrity: No direct loss is represented by this metric.VAHighVulnerable-system availability: A successful attack can cause a major loss.SCNoneSubsequent-system confidentiality: No direct loss is represented by this metric.SINoneSubsequent-system integrity: No direct loss is represented by this metric.SANoneSubsequent-system availability: No direct loss is represented by this metric.- Post-exploitation / living off the land
- No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
03
Patch and workaround
Operational remediation based on structured source evidence.
- Status
?
Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change. - Fix availability varies by product
- Affected
- rsync as a component of Red Hat Enterprise Linux 10
- rsync-daemon as a component of Red Hat Enterprise Linux 10
- rsync-rrsync as a component of Red Hat Enterprise Linux 10
- rsync.src as a component of Red Hat Enterprise Linux 10
- rsync as a component of Red Hat Enterprise Linux 6
- rsync.src as a component of Red Hat Enterprise Linux 6
- rsync as a component of Red Hat Enterprise Linux 7
- rsync.src as a component of Red Hat Enterprise Linux 7
- rsync as a component of Red Hat Enterprise Linux 8
- rsync-daemon as a component of Red Hat Enterprise Linux 8
- rsync.src as a component of Red Hat Enterprise Linux 8
- rsync as a component of Red Hat Enterprise Linux 9
- rsync-daemon as a component of Red Hat Enterprise Linux 9
- rsync-rrsync as a component of Red Hat Enterprise Linux 9
- rsync.src as a component of Red Hat Enterprise Linux 9
- openshift/ose-rhel-coreos-8 as a component of Red Hat OpenShift Container Platform 4
- openshift/ose-rhel-coreos-9 as a component of Red Hat OpenShift Container Platform 4
- Action
- Use the product-specific evidence above. Patch only products with a verified fixed release, and keep every affected or under-investigation state without a matching fix in the remediation queue.
- Workaround
- To mitigate this issue, rsync clients can be configured to disable incremental recursion when pulling from untrusted sources. This can be achieved by using the `--no-inc-recursive` option. Example: `rsync --no-inc-recursive [OPTIONS] SOURCE DESTINATION` Disabling incremental recursion may affect the efficiency of transfers for large, frequently updated directories.
04
Evidence and provenance
Published 20 May 2026 · Last source change 14 Jul 2026, 20:01 UTC · CWE-125 · Out-of-bounds Read
CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source FIRST · tracked since 2026-08-14
?
The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.European sourceENISA EUVD · EUVD-2026-31012
Product sourceVendor CSAF · Red Hat Product Security
Remediation sourceVendor CSAF · Red Hat Product Security
CWE sourceCNA
NVD statusNVD enriched
Core structured fields are present and their contributing authorities are shown above.
Material change intelligence
View recent updates ↗What changed after publication
- Affected versionsThe structured affected or fixed version information changed.Red Hat Product Security ↗
- Before
- rsync as a component of Red Hat Enterprise Linux 10; rsync-daemon as a component of Red Hat Enterprise Linux 10; rsync-rrsync as a component of Red Hat Enterprise Linux 10; rsync.src as a component of Red Hat Enterprise Linux 10; rsync as a component of Red Hat Enterprise Linux 6; rsync.src as a component of Red Hat Enterprise Linux 6; rsync as a component of Red Hat Enterprise Linux 7; rsync.src as a component of Red Hat Enterprise Linux 7; rsync as a component of Red Hat Enterprise Linux 8; rsync-daemon as a component of Red Hat Enterprise Linux 8; rsync.src as a component of Red Hat Enterprise Linux 8; rsync as a component of Red Hat Enterprise Linux 9; rsync-daemon as a component of Red Hat Enterprise Linux 9; rsync-rrsync as a component of Red Hat Enterprise Linux 9; rsync.src as a component of Red Hat Enterprise Linux 9; openshift/ose-rhel-coreos-9 as a component of Red Hat OpenShift Container Platform 4
- After
- rsync as a component of Red Hat Enterprise Linux 10; rsync-daemon as a component of Red Hat Enterprise Linux 10; rsync-rrsync as a component of Red Hat Enterprise Linux 10; rsync.src as a component of Red Hat Enterprise Linux 10; rsync as a component of Red Hat Enterprise Linux 6; rsync.src as a component of Red Hat Enterprise Linux 6; rsync as a component of Red Hat Enterprise Linux 7; rsync.src as a component of Red Hat Enterprise Linux 7; rsync as a component of Red Hat Enterprise Linux 8; rsync-daemon as a component of Red Hat Enterprise Linux 8; rsync.src as a component of Red Hat Enterprise Linux 8; rsync as a component of Red Hat Enterprise Linux 9; rsync-daemon as a component of Red Hat Enterprise Linux 9; rsync-rrsync as a component of Red Hat Enterprise Linux 9; rsync.src as a component of Red Hat Enterprise Linux 9; openshift/ose-rhel-coreos-8 as a component of Red Hat OpenShift Container Platform 4; openshift/ose-rhel-coreos-9 as a component of Red Hat OpenShift Container Platform 4
Technical terms and abbreviations used in this report
- CVE
- Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
- CVSS
- Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
- EPSS
- Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
- CWE
- Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
- CNA
- CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
- CISA ADP
- Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
- NVD
- National Vulnerability Database: NIST's enrichment service for CVE records.
- CERT / CSIRT
- A computer security incident response team that publishes warnings or coordinates incident response.
- PoC
- Proof of concept: public material that demonstrates or helps reproduce exploitation.
- CSAF
- Common Security Advisory Framework: a machine-readable format for security advisories.
- LoTL
- Living off the land: abuse of legitimate tools or system functions during an attack.