CVE-2026-4851 GRID::Machine versions through 0.127 for Perl allows arbitrary code execution via unsafe deserialization
A malicious remote host can execute arbitrary code on the client via unsafe deserialization in the GRID::Machine Perl RPC library.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-4851?
CVE-2026-4851 is a critical unsafe deserialization vulnerability in CASIANO GRID::Machine, published on 29 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Which versions are affected by CVE-2026-4851?
It affects 1 product.
Products include Casiano Grid\.
How do I fix CVE-2026-4851?
No fix has been published for CVE-2026-4851 yet. Limit exposure of the affected software until one is available.
Upgrade, and only deserialise data from trusted sources or with an allow-list of types. More about Unsafe deserialization.
Is CVE-2026-4851 being exploited?
There is no known exploitation of CVE-2026-4851 in the wild and no public exploit code.
Sources
Also known as GHSA-p6f4-6qxg-8xqv.