CVE-2026-34956: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') in Red Hat Fast Datapath for RHEL 7
CVE-2026-34956 is a medium severity vulnerability affecting Red Hat Fast Datapath for RHEL 7, specifically in Open vSwitch when using conntrack flow with FTP helpers over the userspace datapath. The issue arises from a buffer copy operation without checking the input size, allowing a remote attacker to send an EPASV command longer than 255 characters. This causes a heap access error leading to a crash and denial of service. There are no known exploits in the wild. The vendor advisory does not confirm the availability of a patch or remediation.
AI Analysis
Technical Summary
This vulnerability involves a classic buffer overflow in Red Hat Fast Datapath for RHEL 7's Open vSwitch component when configured with conntrack flow using FTP helpers over the userspace datapath. A remote attacker can trigger a heap access error by sending a crafted FTP stream containing an EPASV command exceeding 255 characters, resulting in a denial of service via crash. The CVSS v3.1 score is 5.9, reflecting a network attack vector with high complexity and no privileges required, causing availability impact only. The vendor advisory linked does not specify any patch or mitigation status.
Potential Impact
Successful exploitation causes a denial of service condition by crashing the affected service due to heap access errors. There is no reported impact on confidentiality or integrity. No known exploits exist in the wild at this time.
Mitigation Recommendations
Patch status is not yet confirmed — check the Red Hat advisory at https://access.redhat.com/security/cve/CVE-2026-34956 for current remediation guidance. Until an official fix is available, consider restricting or monitoring FTP traffic that uses EPASV commands to mitigate potential exploitation. No vendor-provided mitigation or workaround is currently documented.
CVE-2026-34956: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') in Red Hat Fast Datapath for RHEL 7
Description
CVE-2026-34956 is a medium severity vulnerability affecting Red Hat Fast Datapath for RHEL 7, specifically in Open vSwitch when using conntrack flow with FTP helpers over the userspace datapath. The issue arises from a buffer copy operation without checking the input size, allowing a remote attacker to send an EPASV command longer than 255 characters. This causes a heap access error leading to a crash and denial of service. There are no known exploits in the wild. The vendor advisory does not confirm the availability of a patch or remediation.
CVSS v3.1
Score 5.9medium
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability involves a classic buffer overflow in Red Hat Fast Datapath for RHEL 7's Open vSwitch component when configured with conntrack flow using FTP helpers over the userspace datapath. A remote attacker can trigger a heap access error by sending a crafted FTP stream containing an EPASV command exceeding 255 characters, resulting in a denial of service via crash. The CVSS v3.1 score is 5.9, reflecting a network attack vector with high complexity and no privileges required, causing availability impact only. The vendor advisory linked does not specify any patch or mitigation status.
Potential Impact
Successful exploitation causes a denial of service condition by crashing the affected service due to heap access errors. There is no reported impact on confidentiality or integrity. No known exploits exist in the wild at this time.
Mitigation Recommendations
Patch status is not yet confirmed — check the Red Hat advisory at https://access.redhat.com/security/cve/CVE-2026-34956 for current remediation guidance. Until an official fix is available, consider restricting or monitoring FTP traffic that uses EPASV commands to mitigate potential exploitation. No vendor-provided mitigation or workaround is currently documented.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- redhat
- Date Reserved
- 2026-03-31T17:43:41.756Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
- Vendor Advisory Urls
- [{"url":"https://access.redhat.com/security/cve/CVE-2026-34956","vendor":"Red Hat"}]
Threat ID: 69fa191dcbff5d86100ff6d0
Added to database: 5/5/2026, 4:21:49 PM
Last enriched: 6/3/2026, 9:20:17 PM
Last updated: 6/20/2026, 7:32:20 AM
Views: 66
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.