CVE-2026-34956

MEDIUMNVD 5.95.9—
EchelonGraph scoreMEDIUM confidence

Score 5.9 from GitHub Security Advisory published 2026-05-05. NVD baseline CVSS 5.9; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
5.9
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 5.9Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

A flaw was found in Open vSwitch. When Open vSwitch is configured with a conntrack flow using FTP helpers over the userspace datapath, a remote attacker can send a specially crafted FTP stream with an EPASV command exceeding 255 characters. This heap access error can lead to a crash, resulting in a Denial of Service (DoS) for the affected system.

CVSS v3
5.9
EG Score
5.9(medium)
EPSS
32.7%
KEV
Not listed

Published

May 5, 2026

Last Modified

May 5, 2026

Advisory Details (3)

Auto-updated May 5, 2026
Patch available. Sources: redhat.
generic

oss-security - [ADVISORY] CVE-2026-34956: Open vSwitch: Invalid memory access in conntrack FTP alg.

http://www.openwall.com/lists/oss-security/2026/03/31/15
redhat

2453459 – (CVE-2026-34956) CVE-2026-34956 openvswitch: Open vSwitch: Denial of Service via malformed FTP EPASV command

https://bugzilla.redhat.com/show_bug.cgi?id=2453459
redhat Patch Available

cve-details

https://access.redhat.com/security/cve/CVE-2026-34956

Vendor Advisories for CVE-2026-34956(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 9× in last 7d / 42× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 126 total refreshes for this CVE.

  1. 2026-07-15 16:57 UTCEPSS rescore
  2. 2026-07-15 16:57 UTCEPSS rescore
  3. 2026-07-15 02:00 UTCEPSS rescore
  4. 2026-07-13 22:30 UTCEPSS rescore
  5. 2026-07-13 06:13 UTCEPSS rescore
  6. 2026-07-13 06:13 UTCEPSS rescore
  7. 2026-07-12 05:46 UTCEPSS rescore
  8. 2026-07-11 08:27 UTCEPSS rescore
  9. 2026-07-09 19:10 UTCEPSS rescore
  10. 2026-07-08 15:15 UTCEPSS rescore
  11. 2026-07-07 13:46 UTCEPSS rescore
  12. 2026-07-06 16:27 UTCEPSS rescore
  13. 2026-07-06 16:27 UTCEPSS rescore
  14. 2026-07-06 02:23 UTCEPSS rescore
  15. 2026-07-06 02:23 UTCEPSS rescore
  16. 2026-07-05 02:30 UTCEPSS rescore
  17. 2026-07-04 06:31 UTCEPSS rescore
  18. 2026-07-01 15:06 UTCEPSS rescore
  19. 2026-06-30 23:22 UTCEPSS rescore
  20. 2026-06-29 14:06 UTCEPSS rescore
  21. 2026-06-29 14:06 UTCEPSS rescore
  22. 2026-06-28 14:07 UTCEPSS rescore
  23. 2026-06-28 14:07 UTCEPSS rescore
  24. 2026-06-28 04:56 UTCEPSS rescore
  25. 2026-06-28 04:56 UTCEPSS rescore
Show 75 more
  1. 2026-06-27 03:08 UTCEPSS rescore
  2. 2026-06-25 13:49 UTCEPSS rescore
  3. 2026-06-25 13:49 UTCEPSS rescore
  4. 2026-06-24 14:05 UTCEPSS rescore
  5. 2026-06-23 21:33 UTCEPSS rescore
  6. 2026-06-23 21:33 UTCEPSS rescore
  7. 2026-06-22 14:25 UTCEPSS rescore
  8. 2026-06-22 14:25 UTCEPSS rescore
  9. 2026-06-21 14:56 UTCEPSS rescore
  10. 2026-06-21 14:56 UTCEPSS rescore
  11. 2026-06-21 01:59 UTCEPSS rescore
  12. 2026-06-19 19:25 UTCEPSS rescore
  13. 2026-06-19 19:25 UTCEPSS rescore
  14. 2026-06-18 17:52 UTCEPSS rescore
  15. 2026-06-18 17:52 UTCEPSS rescore
  16. 2026-06-17 17:53 UTCEPSS rescore
  17. 2026-06-16 17:52 UTCEPSS rescore
  18. 2026-06-15 17:49 UTCEPSS rescore
  19. 2026-06-14 23:18 UTCEPSS rescore
  20. 2026-06-14 07:52 UTCEG score recompute
  21. 2026-06-14 07:52 UTCVendor advisory
  22. 2026-06-14 07:52 UTCGHSA enrichment
  23. 2026-06-13 23:00 UTCEPSS rescore
  24. 2026-06-12 23:12 UTCEPSS rescore
  25. 2026-06-12 23:12 UTCEPSS rescore
  26. 2026-06-12 06:41 UTCEG score recompute
  27. 2026-06-12 06:41 UTCVendor advisory
  28. 2026-06-12 06:41 UTCGHSA enrichment
  29. 2026-06-11 14:00 UTCEPSS rescore
  30. 2026-06-11 04:40 UTCEG score recompute
  31. 2026-06-11 04:40 UTCVendor advisory
  32. 2026-06-11 04:39 UTCGHSA enrichment
  33. 2026-06-10 22:18 UTCEPSS rescore
  34. 2026-06-10 13:22 UTCEPSS rescore
  35. 2026-06-10 02:08 UTCEG score recompute
  36. 2026-06-10 02:08 UTCVendor advisory
  37. 2026-06-10 02:08 UTCGHSA enrichment
  38. 2026-06-09 00:07 UTCEG score recompute
  39. 2026-06-09 00:07 UTCVendor advisory
  40. 2026-06-09 00:07 UTCGHSA enrichment
  41. 2026-06-08 14:17 UTCEPSS rescore
  42. 2026-06-08 14:17 UTCEPSS rescore
  43. 2026-06-07 22:04 UTCEG score recompute
  44. 2026-06-07 22:04 UTCVendor advisory
  45. 2026-06-07 22:04 UTCGHSA enrichment
  46. 2026-06-07 15:25 UTCEPSS rescore
  47. 2026-06-07 15:25 UTCEPSS rescore
  48. 2026-06-07 15:25 UTCEPSS rescore
  49. 2026-06-06 20:03 UTCEG score recompute
  50. 2026-06-06 20:03 UTCVendor advisory
  51. 2026-06-06 20:03 UTCGHSA enrichment
  52. 2026-06-06 13:47 UTCEPSS rescore
  53. 2026-06-06 13:47 UTCEPSS rescore
  54. 2026-06-05 22:47 UTCEPSS rescore
  55. 2026-06-05 22:47 UTCEPSS rescore
  56. 2026-06-05 17:58 UTCEG score recompute
  57. 2026-06-05 17:58 UTCVendor advisory
  58. 2026-06-05 17:58 UTCGHSA enrichment
  59. 2026-06-05 06:10 UTCEPSS rescore
  60. 2026-06-05 06:10 UTCEPSS rescore
  61. 2026-06-04 15:56 UTCEG score recompute
  62. 2026-06-04 15:56 UTCVendor advisory
  63. 2026-06-04 15:56 UTCGHSA enrichment
  64. 2026-06-04 13:12 UTCEPSS rescore
  65. 2026-06-04 13:12 UTCEPSS rescore
  66. 2026-06-03 13:54 UTCEG score recompute
  67. 2026-06-03 13:54 UTCVendor advisory
  68. 2026-06-03 13:54 UTCGHSA enrichment
  69. 2026-06-02 20:13 UTCEPSS rescore
  70. 2026-06-02 11:52 UTCEG score recompute
  71. 2026-06-02 11:52 UTCVendor advisory
  72. 2026-06-02 11:52 UTCGHSA enrichment
  73. 2026-06-01 13:52 UTCEPSS rescore
  74. 2026-06-01 13:52 UTCEPSS rescore
  75. 2026-06-01 13:51 UTCEPSS rescore

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Frequently asked(5)

What is CVE-2026-34956?
CVE-2026-34956 is a medium vulnerability published on May 5, 2026. A flaw was found in Open vSwitch. When Open vSwitch is configured with a conntrack flow using FTP helpers over the userspace datapath, a remote attacker can send a specially crafted FTP stream with an EPASV command exceeding 255 characters. This heap access error can lead to a crash, resulting in a…
When was CVE-2026-34956 disclosed?
CVE-2026-34956 was first published in the National Vulnerability Database on May 5, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-34956 actively exploited?
CVE-2026-34956 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 32.7% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-34956?
CVE-2026-34956 has a CVSS v3 base score of 5.9 (NVD).
How do I remediate CVE-2026-34956?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-34956, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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