CVE-2025-26466

MEDIUMNVD 5.96.4▲
EchelonGraph scoreHIGH confidence

Score elevated to 6.4 because EPSS predicts 38% probability of exploitation within the next 30 days (top 1.6% of all CVEs). NVD baseline CVSS 5.9 retained for reference. Confidence: see factors.

Triggered by: EPSS exploit prediction ≥85%
Sources: epss, ghsa, nvd
Elevated
6.4EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 40%CVSS: 5.9Exploit: Elevated riskExposed: 0

A fix is available — apply it.

A flaw was found in the OpenSSH package. For each ping packet the SSH server receives, a pong packet is allocated in a memory buffer and stored in a queue of packages. It is only freed when the server/client key exchange has finished. A malicious client may keep sending such packages, leading to an uncontrolled increase in memory consumption on the server side. Consequently, the server may become unavailable, resulting in a denial of service attack.

CVSS v3
5.9
EG Score
6.4(high)
EG Risk
45(Track)
EG Risk 45/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity64% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
40%
EPSS %ILE
99%
KEV
Not listed

Published

February 28, 2025

Last Modified

June 30, 2026

Advisory Details (10)

Auto-updated Jun 25, 2026
🔬 Proof of concept available. Patch available. Sources: redhat.
generic

NetApp Product Security

https://security.netapp.com/advisory/ntap-20250228-0002/
generic

CVE-2025-26466

https://security-tracker.debian.org/tracker/CVE-2025-26466
generic🟡 PoC Available

1237041 – (CVE-2025-26466) VUL-0: CVE-2025-26466: openssh,openssh8.4: DoS attack against OpenSSH's client and server

https://bugzilla.suse.com/show_bug.cgi?id=1237041
generic

Full Disclosure: APPLE-SA-05-12-2025-4 macOS Sonoma 14.7.6

http://seclists.org/fulldisclosure/2025/May/8
generic

Full Disclosure: APPLE-SA-05-12-2025-3 macOS Sequoia 15.5

http://seclists.org/fulldisclosure/2025/May/7
generic🟡 PoC Available

Full Disclosure: Re: MitM attack against OpenSSH's VerifyHostKeyDNS-enabled client

http://seclists.org/fulldisclosure/2025/Feb/18
generic🟡 PoC Available
https://www.qualys.com/2025/02/18/openssh-mitm-dos.txt
generic🟡 PoC Available

oss-sec: MitM attack against OpenSSH's VerifyHostKeyDNS-enabled client

https://seclists.org/oss-sec/2025/q1/144
redhat

2345043 – (CVE-2025-26466) CVE-2025-26466 openssh: Denial-of-service in OpenSSH

https://bugzilla.redhat.com/show_bug.cgi?id=2345043
redhat Patch Available

cve-details

https://access.redhat.com/security/cve/CVE-2025-26466

Vendor Advisories for CVE-2025-26466(1)

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

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntussh-askpass-gnome (1:9.7p1-7ubuntu4.2) @ oracular2026-05-30ubuntu

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(8 across 8 ecosystems)
Alpine:v3.19(1)
PackageVulnerable rangeFixed inDependents
openssh—9.6_p1-r2—
Alpine:v3.20(1)
PackageVulnerable rangeFixed inDependents
openssh—9.7_p1-r5—
Alpine:v3.21(1)
PackageVulnerable rangeFixed inDependents
openssh—9.9_p2-r0—
Alpine:v3.22(1)
PackageVulnerable rangeFixed inDependents
openssh—9.9_p2-r0—
Alpine:v3.23(1)
PackageVulnerable rangeFixed inDependents
openssh—9.9_p2-r0—
Alpine:v3.24(1)
PackageVulnerable rangeFixed inDependents
openssh—9.9_p2-r0—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
openssh—1:9.9p2-1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
openssh—1:9.9p2-1—

Weakness Classification(2)

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

Additional Vendor Advisories

(1)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 5× in last 7d / 23× 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 119 total refreshes for this CVE.

  1. 2026-09-20 20:15 UTCEPSS rescore
  2. 2026-09-18 19:27 UTCEPSS rescore
  3. 2026-09-16 14:06 UTCEPSS rescore
  4. 2026-09-16 05:13 UTCEPSS rescore
  5. 2026-09-15 03:09 UTCEPSS rescore
  6. 2026-09-13 19:09 UTCOSV refresh
  7. 2026-09-12 15:00 UTCEPSS rescore
  8. 2026-09-11 09:35 UTCEPSS rescore
  9. 2026-09-10 09:33 UTCEPSS rescore
  10. 2026-09-08 21:59 UTCEPSS rescore
  11. 2026-09-06 13:46 UTCEPSS rescore
  12. 2026-09-06 13:46 UTCEPSS rescore
  13. 2026-09-05 15:28 UTCEPSS rescore
  14. 2026-09-04 05:05 UTCEPSS rescore
  15. 2026-09-02 14:11 UTCEPSS rescore
  16. 2026-09-01 04:38 UTCEPSS rescore
  17. 2026-08-30 19:16 UTCEPSS rescore
  18. 2026-08-30 01:21 UTCEPSS rescore
  19. 2026-08-28 21:40 UTCEPSS rescore
  20. 2026-08-27 14:24 UTCEPSS rescore
  21. 2026-08-25 20:39 UTCOSV refresh
  22. 2026-08-25 13:47 UTCEPSS rescore
  23. 2026-08-21 23:48 UTCEPSS rescore
  24. 2026-08-20 22:54 UTCEPSS rescore
  25. 2026-08-19 17:03 UTCEPSS rescore
Show 75 more
  1. 2026-08-18 13:47 UTCEPSS rescore
  2. 2026-08-17 13:46 UTCEPSS rescore
  3. 2026-08-16 14:55 UTCEPSS rescore
  4. 2026-08-16 02:13 UTCEPSS rescore
  5. 2026-08-16 02:13 UTCEPSS rescore
  6. 2026-08-15 01:29 UTCEPSS rescore
  7. 2026-08-13 21:59 UTCEPSS rescore
  8. 2026-08-12 13:50 UTCEPSS rescore
  9. 2026-08-09 12:50 UTCOSV refresh
  10. 2026-08-07 16:26 UTCEPSS rescore
  11. 2026-08-06 13:46 UTCEPSS rescore
  12. 2026-08-05 19:16 UTCEPSS rescore
  13. 2026-08-03 10:35 UTCEPSS rescore
  14. 2026-08-02 02:25 UTCEPSS rescore
  15. 2026-08-01 04:15 UTCEPSS rescore
  16. 2026-07-30 16:27 UTCEPSS rescore
  17. 2026-07-30 01:29 UTCEPSS rescore
  18. 2026-07-28 15:35 UTCEPSS rescore
  19. 2026-07-27 14:12 UTCEPSS rescore
  20. 2026-07-26 14:53 UTCEPSS rescore
  21. 2026-07-25 14:17 UTCEPSS rescore
  22. 2026-07-24 14:17 UTCEPSS rescore
  23. 2026-07-24 13:41 UTCOSV refresh
  24. 2026-07-23 14:17 UTCEPSS rescore
  25. 2026-07-23 02:52 UTCEG score recompute▲ 0.50
  26. 2026-07-22 14:07 UTCEPSS rescore
  27. 2026-07-22 14:07 UTCEPSS rescore
  28. 2026-07-21 15:24 UTCEPSS rescore
  29. 2026-07-20 17:07 UTCEPSS rescore
  30. 2026-07-19 02:28 UTCEPSS rescore
  31. 2026-07-19 02:28 UTCEPSS rescore
  32. 2026-07-18 10:03 UTCEPSS rescore
  33. 2026-07-16 17:02 UTCEPSS rescore
  34. 2026-07-15 16:57 UTCEPSS rescore
  35. 2026-07-15 16:57 UTCEPSS rescore
  36. 2026-07-15 01:59 UTCEPSS rescore
  37. 2026-07-13 22:29 UTCEPSS rescore
  38. 2026-07-13 22:29 UTCEPSS rescore
  39. 2026-07-13 06:12 UTCEPSS rescore
  40. 2026-07-13 06:12 UTCEPSS rescore
  41. 2026-07-12 05:46 UTCEPSS rescore
  42. 2026-07-12 05:46 UTCEPSS rescore
  43. 2026-07-11 08:27 UTCEPSS rescore
  44. 2026-07-11 08:26 UTCEPSS rescore
  45. 2026-07-09 19:09 UTCEPSS rescore
  46. 2026-07-07 08:51 UTCOSV refresh
  47. 2026-07-06 16:26 UTCEPSS rescore
  48. 2026-07-04 06:30 UTCEPSS rescore
  49. 2026-07-01 15:06 UTCEPSS rescore
  50. 2026-06-28 14:07 UTCEPSS rescore
  51. 2026-06-28 14:07 UTCEPSS rescore
  52. 2026-06-28 04:55 UTCEPSS rescore
  53. 2026-06-28 04:55 UTCEPSS rescore
  54. 2026-06-27 03:08 UTCEPSS rescore
  55. 2026-06-27 03:08 UTCEPSS rescore
  56. 2026-06-25 13:49 UTCEPSS rescore
  57. 2026-06-25 13:49 UTCEPSS rescore
  58. 2026-06-24 14:04 UTCEPSS rescore
  59. 2026-06-24 14:04 UTCEPSS rescore
  60. 2026-06-23 21:32 UTCEPSS rescore
  61. 2026-06-23 21:32 UTCEPSS rescore
  62. 2026-06-22 14:25 UTCEPSS rescore
  63. 2026-06-22 14:25 UTCEPSS rescore
  64. 2026-06-21 01:59 UTCEPSS rescore
  65. 2026-06-21 01:59 UTCEPSS rescore
  66. 2026-06-18 20:05 UTCOSV refresh
  67. 2026-06-18 17:52 UTCEPSS rescore
  68. 2026-06-18 17:52 UTCEPSS rescore
  69. 2026-06-17 17:52 UTCEPSS rescore
  70. 2026-06-16 17:52 UTCEPSS rescore
  71. 2026-06-16 17:52 UTCEPSS rescore
  72. 2026-06-15 17:48 UTCEPSS rescore
  73. 2026-06-13 22:59 UTCEPSS rescore
  74. 2026-06-12 23:11 UTCEPSS rescore
  75. 2026-06-11 13:59 UTCEPSS rescore

Publicly available exploits

(1 reference)

Working exploit code is in the public domain (1 GitHub PoC). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • GitHub PoCrxerium/CVE-2025-26466
    First seen Feb 18, 2025

    The OpenSSH client and server are vulnerable to a pre-authentication DoS attack between versions 9.5p1 to 9.9p1 (inclusive) that causes memory and CPU consumption

    Open source ↗

Related CVEs(same vendor + same CWE)

Same vendor

1 shown

ubuntu:USN-7270-1

Frequently asked(5)

What is CVE-2025-26466?
CVE-2025-26466 is a medium vulnerability published on February 28, 2025. A flaw was found in the OpenSSH package. For each ping packet the SSH server receives, a pong packet is allocated in a memory buffer and stored in a queue of packages. It is only freed when the server/client key exchange has finished. A malicious client may keep sending such packages, leading to an…
When was CVE-2025-26466 disclosed?
CVE-2025-26466 was first published in the National Vulnerability Database on February 28, 2025, with the most recent update on June 30, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2025-26466 actively exploited?
CVE-2025-26466 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 40% probability of exploitation in the next 30 days, which ranks it in the top 1.4% of all scored CVEs.
What is the CVSS score of CVE-2025-26466?
CVE-2025-26466 has a CVSS v3 base score of 5.9 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 6.4.
How do I remediate CVE-2025-26466?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2025-26466, 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.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2025-26466

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