Security Resilience

CVE-2023-2868

RCE in Barracuda Email Security Gateway 300 Firmware 5.1.3.001 – 9.2.0.006

CISA KEVActive ExploitationEUVD ExploitedRCECommand Injection
Published
24 May 2023
Modified
24 October 2025
KEV Added
26 May 2023
Patch / advisory
CVSS Score v3.1 9.4
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L
EPSS Score 0.88 99.8th percentile
Risk Priority 95 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2023-2868 is a critical-severity Improper Input Validation (CWE-20) vulnerability in Barracuda Email Security Gateway 300 Firmware. Its CVSS base score is 9.4 (Critical).

Operationally, ranked in the top 0.2% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

A remote command injection vulnerability affects the Barracuda Email Security Gateway appliance in versions 5.1.3.001 through 9.2.0.006. The flaw stems from incomplete input validation when processing .tar archives, specifically the names of files contained within them. An attacker can craft archive entries that cause Perl's qx operator to execute arbitrary system commands with the privileges of the Email Security Gateway product. The issue is tracked under CWE-20 and CWE-77 and carries a CVSS 3.1 score of 9.4.

An unauthenticated remote attacker can exploit the vulnerability by sending a specially formatted .tar file to the appliance. Successful exploitation grants the ability to run commands on the underlying system, potentially leading to full compromise of the email security gateway with impacts on confidentiality, integrity, and limited availability.

Barracuda addressed the issue via patch BNSF-36456, which was automatically deployed to all customer appliances. Public advisories from Barracuda and CISA confirm the fix and note that the vulnerability has been observed in active exploitation campaigns.

The CVE appears in CISA's Known Exploited Vulnerabilities catalog. Its EPSS score reached a peak of 0.9145 and currently stands at 0.8921, indicating sustained exploitation interest after disclosure.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

A remote command injection vulnerability exists in the Barracuda Email Security Gateway (appliance form factor only) product effecting versions 5.1.3.001-9.2.0.006. The vulnerability arises out of a failure to comprehensively sanitize the processing of .tar file (tape archives). The vulnerability stems…

more

from incomplete input validation of a user-supplied .tar file as it pertains to the names of the files contained within the archive. As a consequence, a remote attacker can specifically format these file names in a particular manner that will result in remotely executing a system command through Perl's qx operator with the privileges of the Email Security Gateway product. This issue was fixed as part of BNSF-36456 patch. This patch was automatically applied to all customer appliances.

CWE(s)
KEV Date Added
26 May 2023

Related Threats

Threat-Actor AttributionAI

UNC4841
Mandiant publicly attributed mass exploitation of this Barracuda ESG zero-day to UNC4841 espionage operations (2023 reporting).
Google LLC (civil insider-recruitment defendant)
North Korea Cyber Group Conducts Global Espionage Campaign to Advance Regime’s Military and Nuclear Programs | CISA
Microsoft Corp. (Salesforce / Slack engineer recruitment claims)
North Korea Cyber Group Conducts Global Espionage Campaign to Advance Regime’s Military and Nuclear Programs | CISA
North Korea Cyber Group Conducts Global Espionage Campaign to Advance Regime’s Military and Nuclear Programs | CISA
AnonOps
North Korea Cyber Group Conducts Global Espionage Campaign to Advance Regime’s Military and Nuclear Programs | CISA
Storm-0530
North Korea Cyber Group Conducts Global Espionage Campaign to Advance Regime’s Military and Nuclear Programs | CISA
Maui ransomware
North Korea Cyber Group Conducts Global Espionage Campaign to Advance Regime’s Military and Nuclear Programs | CISA
Apple Inc. (Masimo pulse-oximetry trade-secret 2020-2024)
2023 Top Routinely Exploited Vulnerabilities | CISA
Clop
2023 Top Routinely Exploited Vulnerabilities | CISA
l group
North Korea Cyber Group Conducts Global Espionage Campaign to Advance Regime’s Military and Nuclear Programs | CISA

CVEs Like This One

CVE-2024-3400Shared CWE-20, CWE-77both on KEV
CVE-2018-19949Shared CWE-20, CWE-77both on KEV
CVE-2007-3010Shared CWE-77both on KEV
CVE-2020-25079Shared CWE-77both on KEV
CVE-2021-35247Shared CWE-20both on KEV
CVE-2022-47966Shared CWE-20both on KEV
CVE-2022-40765Shared CWE-77both on KEV
CVE-2019-0604Shared CWE-20both on KEV
CVE-2022-2856Shared CWE-20both on KEV
CVE-2016-3714Shared CWE-20both on KEV

Affected Assets

barracuda
email security gateway 300 firmware
5.1.3.001 — 9.2.0.006
barracuda
email security gateway 400 firmware
5.1.3.001 — 9.2.0.006
barracuda
email security gateway 600 firmware
5.1.3.001 — 9.2.0.006
barracuda
email security gateway 800 firmware
5.1.3.001 — 9.2.0.006
barracuda
email security gateway 900 firmware
5.1.3.001 — 9.2.0.006

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-20

Security testing and developer training directly verify and enforce proper input validation, reducing exploitability of injection and malformed-data weaknesses.

addresses: CWE-20

Security testing and evaluation at multiple SDLC stages directly detects missing or flawed input validation, with the required remediation process ensuring fixes are applied.

addresses: CWE-20

Directly implements checks on information inputs to reject invalid data before processing.

addresses: CWE-20

Spam protection mechanisms perform filtering and detection on inbound/outbound messages, directly compensating for missing or weak input validation of unsolicited content.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

blocks

A.8.25 mandates security requirements, secure coding guidelines, checkpoints, testing (incl. code scans) and developer training in the SDLC, which reaches a slice of input validation defects but leaves the majority (incomplete enforcement, second-order inputs, parser differentials, post-validation canonicalization) unaddressed as in the SA-3 and A.8.28 anchors.

blocks

Mandating input controls that include integrity checks and input validation ensures that untrusted data is examined before use, blocking the root cause of many injection and malformed-data weaknesses.

blocks

Security-by-design principles explicitly call for data validation and sanitization at every layer, reducing the chance that malformed or malicious input will be processed without scrutiny.

prevents

Requiring language-specific secure coding standards, peer review, SAST and documented mitigation of common programming errors forces validation of all inputs before they are trusted.

finds

Testing against a defined set of requirements and using code review plus vulnerability scanning forces validation of inputs and handling of unanticipated conditions, reducing the chance that malformed data will be accepted.

Hardening callouts derived

DISA STIG baselines are authored against specific weaknesses. Where this CVE cites a broad weakness class, the mapping is not asserted at that abstraction (owner ruling, 2026-09-25: grade only at Base and below), so no rule is shown here rather than a rule shown against the wrong grain.

  • No fine-grained STIG row for CWE-20, a class-level weakness, and none of its children carries one either.
  • No fine-grained STIG row for CWE-77, a class-level weakness, and none of its children carries one either.

References