CVE-2026-4851: GRID::Machine versions through 0.127 for Perl allows arbitrary code execution via unsafe deserialization. GRID::Machine provides Remote Procedure Cal...

Description

GRID::Machine versions through 0.127 for Perl allows arbitrary code execution via unsafe deserialization. GRID::Machine provides Remote Procedure Calls (RPC) over SSH for Perl. The client connects to remote hosts to execute code on them. A compromised or malicious remote host can execute arbitrary code back on the client through unsafe deserialization in the RPC protocol. read_operation() in lib/GRID/Machine/Message.pm deserialises values from the remote side using eval() $arg .= '$VAR1'; my $val = eval "no strict; $arg"; # line 40-41 $arg is raw bytes from the protocol pipe. A compromised remote host can embed arbitrary perl in the Dumper-formatted response: $VAR1 = do { system("..."); }; This executes on the client silently on every RPC call, as the return values remain correct. This functionality is by design but the trust requirement for the remote host is not documented in the distribution.

Metrics

CVSS 3.1

9.8/10

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

EPSS Probability

0.47%

37.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions	Update
Casiano	Grid\	<= 0.127	Machine

References

https://www.openwall.com/lists/oss-security/2026/03/26/6Mailing List
http://www.openwall.com/lists/oss-security/2026/03/26/6Mailing List

Timeline

Published: Mar 29, 2026
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2026-4851?

GRID::Machine versions through 0.127 for Perl allows arbitrary code execution via unsafe deserialization. GRID::Machine provides Remote Procedure Calls (RPC) over SSH for Perl. The client connects to remote hosts to execute code on them. A compromised or malicious remote host can execute arbitrary code back on the client through unsafe deserialization in the RPC protocol. read_operation() in lib/GRID/Machine/Message.pm deserialises values from the remote side using eval() $arg .= '$VAR1'; my $val = eval "no strict; $arg"; # line 40-41 $arg is raw bytes from the protocol pipe. A compromised remote host can embed arbitrary perl in the Dumper-formatted response: $VAR1 = do { system("..."); }; This executes on the client silently on every RPC call, as the return values remain correct. This functionality is by design but the trust requirement for the remote host is not documented in the distribution.

How severe is CVE-2026-4851?

CVE-2026-4851 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 0.47% probability of exploitation in the next 30 days.

How do I fix CVE-2026-4851?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.