CVE-2026-4851

CVE-2026-4851 is a critical-severity vulnerability in Casiano Grid with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-95.

Key facts

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.

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 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-4851 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (37th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-4851?
CVE-2026-4851 affects Casiano Grid. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-4851?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2026-4851 have an EU (EUVD) identifier?
Yes. CVE-2026-4851 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-16957.
When was CVE-2026-4851 published?
CVE-2026-4851 was published on 2026-03-29 and last updated on 2026-06-17.

References

Affected products (1)

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