Is CVE-2026-43620 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-43620 being exploited in the wild.

How severe is CVE-2026-43620?

Medium severity, with a CVSS score of 6.5, published 20 May 2026.

Is there a fix for CVE-2026-43620?

A patch was published on 2026-05-20: Rsync version 3.4.3 released. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-43620 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-43620?

Check whether you run RsyncProject Rsync at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-43620: Rsync out-of-bounds array read in recv_files

CVE-2026-43620 · Severity: medium · CVSS 6.5 · Published 2026-05-20

Rsync is a widely used utility for synchronizing files between different systems. A vulnerability in the client-side software allows a malicious server to crash the rsync client during a file transfer. This could be used to disrupt automated backup or deployment processes, though it does not appear to allow for data theft or unauthorized system access.

Technologies: RsyncProject Rsync. Vendors: RsyncProject.

Quick answers

Is CVE-2026-43620 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-43620 being exploited in the wild.
How severe is CVE-2026-43620?: Medium severity, with a CVSS score of 6.5, published 20 May 2026.
Which products and versions are affected?: RsyncProject Rsync <= 3.4.2.
Is there a fix for CVE-2026-43620?: A patch was published on 2026-05-20: Rsync version 3.4.3 released. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-43620 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-43620?: Check whether you run RsyncProject Rsync at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

An out-of-bounds array read exists in the recv_files() function within receiver.c. By setting the CF_INC_RECURSE flag and providing a specially crafted file list where the first entry is not the leading dot directory, a malicious sender can cause the receiver to set an internal index (parent_ndx) to -1. When a subsequent transfer record with ndx=0 and specific flags is processed, the receiver attempts to read memory 8 bytes before the allocated pointer array. This results in a null or invalid pointer dereference and a deterministic SIGSEGV crash. The vulnerability is reachable via both rsync:// and remote-shell (SSH) pulls. A fix is available in version 3.4.3, and a workaround is to use the --no-inc-recursive flag.

Affected products

RsyncProject rsync <= 3.4.2

Timeline

2026-05-19: disclosed: Vulnerability reported by Pratham Gupta.
2026-05-20: patched: Rsync version 3.4.3 released.
2026-05-20: advisory

References

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