Description
When generating an ICMP Destination Unreachable or Packet Too Big response, the handler copies a portion of the original packet into the ICMP error body using the IP header's self-declared total length (ip_tot_len for IPv4, ip6_plen for IPv6) without validating it against the actual packet buffer size. A VM can send a short packet with an inflated IP length field that triggers an ICMP error (e.g., by hitting a reject ACL), causing ovn-controller to read heap memory beyond the valid packet data and include it in the ICMP response sent back to the VM.
Published: 2026-04-24
Score: 6.5 Medium
EPSS: < 1% Very Low
KEV: No
Impact: Information disclosure through ICMP error responses
Action: Apply patch
AI Analysis

Impact

A heap over‑read occurs when the system generates ICMP Destination Unreachable or Packet Too Big replies; the code copies data from the source packet using the packet’s declared total length without verifying that the declared length is within the actual buffer. The result is that the generated ICMP error includes memory that lies beyond the end of the original packet. An attacker can craft a short packet with an inflated length field, which triggers the over‑read and causes the controller to transmit a malformed ICMP message that leaks arbitrary heap contents. The vulnerability does not provide code execution but could expose sensitive data such as kernel pointers or credentials.

Affected Systems

All Red Hat Fast Datapath releases for RHEL 7, RHEL 8, and RHEL 9 are affected. No specific versioning information is supplied by the vendor. The issue applies to the ovn-controller component within the Fast Datapath stack.

Risk and Exploitability

The CVSS score of 6.5 indicates a moderate impact, and the EPSS score of less than 1% suggests that exploitation is considered unlikely in the near term. The vulnerability is not listed in CISA’s KEV catalog. Attackers would need access to a virtual machine in the same environment that can send a custom IP packet with a fabricated length field and cause the ovn-controller to respond with an ICMP error. In a typical deployment, this requires the attacker to control traffic that reaches the controller, making the risk moderate but non‑negligible for exposed or poorly segmented networks.

Generated by OpenCVE AI on April 28, 2026 at 06:53 UTC.

Remediation

Vendor Workaround

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.


OpenCVE Recommended Actions

  • Check the Red Hat security portal for a vendor‑released patch for CVE‑2026‑5265 and apply the update as soon as it is available.
  • Until a patch is available, isolate the affected virtual machine or network segment and prevent it from sending large ICMP error traffic to the ovn‑controller.
  • Configure firewall or ACL rules to drop ICMP Destination Unreachable and Packet Too Big messages originating from untrusted hosts, thereby reducing the chance of memory leakage.

Generated by OpenCVE AI on April 28, 2026 at 06:53 UTC.

Tracking

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Advisories

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History

Mon, 01 Jun 2026 01:45:00 +0000

Type Values Removed Values Added
References

Wed, 29 Apr 2026 19:00:00 +0000


Wed, 29 Apr 2026 13:15:00 +0000


Wed, 29 Apr 2026 09:15:00 +0000

Type Values Removed Values Added
CPEs cpe:/o:redhat:enterprise_linux:10::fastdatapath

Tue, 28 Apr 2026 09:45:00 +0000

Type Values Removed Values Added
First Time appeared Redhat fast Datapath
Vendors & Products Redhat fast Datapath

Sat, 25 Apr 2026 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

threat_severity

Moderate


Fri, 24 Apr 2026 19:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Fri, 24 Apr 2026 14:30:00 +0000


Fri, 24 Apr 2026 13:15:00 +0000

Type Values Removed Values Added
Description When generating an ICMP Destination Unreachable or Packet Too Big response, the handler copies a portion of the original packet into the ICMP error body using the IP header's self-declared total length (ip_tot_len for IPv4, ip6_plen for IPv6) without validating it against the actual packet buffer size. A VM can send a short packet with an inflated IP length field that triggers an ICMP error (e.g., by hitting a reject ACL), causing ovn-controller to read heap memory beyond the valid packet data and include it in the ICMP response sent back to the VM.
Title Ovn: ovn: heap over-read in icmp error response generation - security issue
First Time appeared Redhat
Redhat enterprise Linux
Weaknesses CWE-130
CPEs cpe:/o:redhat:enterprise_linux:7::fastdatapath
cpe:/o:redhat:enterprise_linux:8::fastdatapath
cpe:/o:redhat:enterprise_linux:9::fastdatapath
Vendors & Products Redhat
Redhat enterprise Linux
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:H'}


Subscriptions

Redhat Enterprise Linux Fast Datapath
cve-icon MITRE

Status: PUBLISHED

Assigner: redhat

Published:

Updated: 2026-06-01T00:15:34.720Z

Reserved: 2026-03-31T17:33:09.225Z

Link: CVE-2026-5265

cve-icon Vulnrichment

Updated: 2026-04-24T13:37:06.533Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-04-24T13:16:21.770

Modified: 2026-04-29T19:16:24.470

Link: CVE-2026-5265

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-04-06T00:00:00Z

Links: CVE-2026-5265 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-04-28T09:17:58Z

Weaknesses