CVE-2025-26466

MEDIUMNVD 5.96.4
EchelonGraph scoreHIGH confidence

“▲” beside the score: it is higher than NVD's CVSS score.

Score elevated to 6.4 because EPSS predicted 39% probability of exploitation within the next 30 days (98th percentile of EPSS-scored CVEs) when EchelonGraph scored this CVE. NVD baseline CVSS 5.9 retained for reference. Confidence: see factors.

Triggered by: EPSS exploit prediction (continuous uplift above 30%)
Sources: EPSS, GitHub Security Advisory, NVD CVSS v3
Elevated

Also known asEUVD-2025-5920 (ENISA EUVD) · GHSA-m92w-x6j2-5gc5 (GitHub Security Advisories)Source: ENISA EUVD

6.4EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • Public exploit or proof-of-concept code is available
CISA-KEV: Not listedEPSS PROB: 39%CVSS: 5.9Exploit: Public PoCExposed services: Not assessed

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
6.4MEDIUMhigh confidence
EG Risk
43
EG Risk 43/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity59% × 45%
Impact severity (EG Severity): CVSS 5.9 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation40% × 40%
EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
39%
EPSS %ILE
98th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (6.4): severity, escalated by confirmed exploitation. This CVE's 6.4 is EPSS's lift toward 9.0 from its impact severity (EG Severity, CVSS 5.9 MEDIUM): a likelihood of exploitation, not impact.

EG Severity
5.9 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
39% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-25). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at low or medium mission impact; Track* at high (mission-essential systems).CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines.

Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

February 28, 2025

Last Modified

October 21, 2026

Advisory Details (10)

Auto-updated Jun 25, 2026
Patch available. Sources: redhat.
Web page

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
Web page

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

http://seclists.org/fulldisclosure/2025/May/8
Web page

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

http://seclists.org/fulldisclosure/2025/May/7
Web page

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

http://seclists.org/fulldisclosure/2025/Feb/18
Web page

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

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

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

https://bugzilla.redhat.com/show_bug.cgi?id=2345043
Red HatMentions a patch (unverified)

cve-details

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

Patch Availability(3)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntussh-askpass-gnome (1:8.9p1-3ubuntu0.11) @ jammy2026-10-21ubuntu
redhatopenssh-0:9.9p1-7.el10_02025-05-13redhat
redhatopenssh-0:8.7p1-45.el92025-05-13redhat

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 rangeFix by version rangeDependents
openssh—
  • every version up to 9.6_p1-r2: fixed in 9.6_p1-r2
—
Alpine:v3.20(1)
PackageVulnerable rangeFix by version rangeDependents
openssh—
  • every version up to 9.7_p1-r5: fixed in 9.7_p1-r5
—
Alpine:v3.21(1)
PackageVulnerable rangeFix by version rangeDependents
openssh—
  • every version up to 9.9_p2-r0: fixed in 9.9_p2-r0
—
Alpine:v3.22(1)
PackageVulnerable rangeFix by version rangeDependents
openssh—
  • every version up to 9.9_p2-r0: fixed in 9.9_p2-r0
—
Alpine:v3.23(1)
PackageVulnerable rangeFix by version rangeDependents
openssh—
  • every version up to 9.9_p2-r0: fixed in 9.9_p2-r0
—
Alpine:v3.24(1)
PackageVulnerable rangeFix by version rangeDependents
openssh—
  • every version up to 9.9_p2-r0: fixed in 9.9_p2-r0
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
openssh—
  • every version up to 1:9.9p2-1: fixed in 1:9.9p2-1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
openssh—
  • every version up to 1:9.9p2-1: fixed in 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 / 57× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 96 of 185 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 4 repeat rows among the latest 100 are merged into the row they repeat. The 89 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-31 16:30 UTCEPSS rescoreEPSS 39% · 98th percentile
  2. 2026-10-30 16:32 UTCEPSS rescoreEPSS 39% · 98th percentile
  3. 2026-10-29 16:31 UTCEPSS rescoreEPSS 39% · 98th percentile
  4. 2026-10-28 16:30 UTCEPSS rescoreEPSS 39% · 98th percentile
  5. 2026-10-27 16:30 UTCEPSS rescoreEPSS 39% · 98th percentile
  6. 2026-10-26 16:29 UTCEPSS rescoreEPSS 39% · 98th percentile
  7. 2026-10-25 16:34 UTCEG score recompute▼ 0.10
  8. 2026-10-25 16:34 UTCVendor advisory
  9. 2026-10-25 16:33 UTCGHSA enrichmentGHSA-m92w-x6j2-5gc5 · GitHub CVSS 5.9
  10. 2026-10-25 16:31 UTCEPSS rescoreEPSS 39% · 98th percentile
  11. 2026-10-24 16:30 UTCEPSS rescoreEPSS 41% · 98th percentile
  12. 2026-10-23 16:30 UTCEPSS rescoreEPSS 41% · 98th percentile
  13. 2026-10-22 16:32 UTCEPSS rescoreEPSS 41% · 98th percentile
  14. 2026-10-21 17:28 UTCVendor advisory
  15. 2026-10-21 17:28 UTCGHSA enrichmentGHSA-m92w-x6j2-5gc5 · GitHub CVSS 5.9
  16. 2026-10-21 17:13 UTCEG score recompute
  17. 2026-10-21 17:13 UTCVendor advisory
  18. 2026-10-21 17:13 UTCGHSA enrichmentGHSA-m92w-x6j2-5gc5 · GitHub CVSS 5.9
  19. 2026-10-21 16:30 UTCEPSS rescoreEPSS 41% · 98th percentile
  20. 2026-10-20 16:31 UTCEPSS rescoreEPSS 41% · 98th percentile
  21. 2026-10-19 16:30 UTCEPSS rescoreEPSS 41% · 98th percentile
  22. 2026-10-18 05:42 UTCEG score recompute
  23. 2026-10-17 16:32 UTCEPSS rescoreEPSS 41% · 98th percentile
  24. 2026-10-16 16:38 UTCEPSS rescoreEPSS 41% · 98th percentile
  25. 2026-10-15 16:30 UTCEPSS rescoreEPSS 41% · 98th percentile
Show 71 more
  1. 2026-10-15 02:52 UTCVendor advisory
  2. 2026-10-15 02:52 UTCGHSA enrichmentGHSA-m92w-x6j2-5gc5 · GitHub CVSS 5.9
  3. 2026-10-15 02:00 UTCEG score recompute
  4. 2026-10-15 02:00 UTCVendor advisory
  5. 2026-10-15 01:59 UTCGHSA enrichmentGHSA-m92w-x6j2-5gc5 · GitHub CVSS 5.9
  6. 2026-10-14 16:31 UTCEPSS rescoreEPSS 41% · 98th percentile
  7. 2026-10-13 16:32 UTCEPSS rescoreEPSS 41% · 98th percentile
  8. 2026-10-12 17:15 UTCEG score recompute
  9. 2026-10-11 20:47 UTCEG score recompute
  10. 2026-10-11 18:57 UTCEG score recompute
  11. 2026-10-11 15:36 UTCEG score recompute
  12. 2026-10-11 13:47 UTCEPSS rescoreEPSS 41% · 98th percentile
  13. 2026-10-10 19:59 UTCEPSS rescoreEPSS 41% · 98th percentile
  14. 2026-10-09 20:06 UTCEPSS rescoreEPSS 41% · 98th percentile
  15. 2026-10-08 22:24 UTCVendor advisory
  16. 2026-10-08 22:24 UTCGHSA enrichmentGHSA-m92w-x6j2-5gc5 · GitHub CVSS 5.9
  17. 2026-10-08 22:13 UTCEG score recompute
  18. 2026-10-08 22:13 UTCVendor advisory
  19. 2026-10-08 22:13 UTCGHSA enrichmentGHSA-m92w-x6j2-5gc5 · GitHub CVSS 5.9
  20. 2026-10-08 17:09 UTCEPSS rescoreEPSS 41% · 98th percentile
  21. 2026-10-08 12:26 UTCVendor advisory
  22. 2026-10-08 12:26 UTCGHSA enrichmentGHSA-m92w-x6j2-5gc5 · GitHub CVSS 5.9
  23. 2026-10-08 12:07 UTCVendor advisory
  24. 2026-10-08 12:07 UTCGHSA enrichmentGHSA-m92w-x6j2-5gc5 · GitHub CVSS 5.9
  25. 2026-10-08 09:18 UTCVendor advisory
  26. 2026-10-08 09:18 UTCGHSA enrichmentGHSA-m92w-x6j2-5gc5 · GitHub CVSS 5.9
  27. 2026-10-08 08:57 UTCEG score recompute▲ 0.10
  28. 2026-10-08 08:57 UTCVendor advisory
  29. 2026-10-08 08:57 UTCGHSA enrichmentGHSA-m92w-x6j2-5gc5 · GitHub CVSS 5.9
  30. 2026-10-07 23:46 UTCEPSS rescoreEPSS 41% · 98th percentile
  31. 2026-10-06 15:16 UTCEPSS rescoreEPSS 41% · 98th percentile
  32. 2026-10-05 17:42 UTCEPSS rescoreEPSS 40% · 98th percentile
  33. 2026-10-03 14:24 UTCEPSS rescoreEPSS 40% · 98th percentile
  34. 2026-10-02 21:40 UTCOSV refresh
  35. 2026-10-02 16:26 UTCEPSS rescoreEPSS 40% · 98th percentile
  36. 2026-10-01 19:48 UTCEPSS rescoreEPSS 40% · 98th percentile
  37. 2026-09-30 15:02 UTCEPSS rescoreEPSS 40% · 98th percentile
  38. 2026-09-28 13:50 UTCEPSS rescoreEPSS 40% · 98th percentile
  39. 2026-09-26 15:58 UTCEPSS rescoreEPSS 40% · 98th percentile
  40. 2026-09-26 00:24 UTCEPSS rescoreEPSS 40% · 98th percentile
  41. 2026-09-24 14:02 UTCEPSS rescoreEPSS 40% · 98th percentile
  42. 2026-09-23 13:46 UTCEPSS rescoreEPSS 40% · 98th percentile
  43. 2026-09-22 14:47 UTCEPSS rescoreEPSS 40% · 98th percentile
  44. 2026-09-20 20:15 UTCEPSS rescoreEPSS 40% · 98th percentile
  45. 2026-09-18 19:27 UTCEPSS rescoreEPSS 40% · 98th percentile
  46. 2026-09-16 14:06 UTCEPSS rescoreEPSS 40% · 98th percentile
  47. 2026-09-16 05:13 UTCEPSS rescoreEPSS 40% · 98th percentile
  48. 2026-09-15 03:09 UTCEPSS rescoreEPSS 40% · 98th percentile
  49. 2026-09-13 19:09 UTCOSV refresh
  50. 2026-09-12 15:00 UTCEPSS rescoreEPSS 40% · 98th percentile
  51. 2026-09-11 09:35 UTCEPSS rescoreEPSS 40% · 98th percentile
  52. 2026-09-10 09:33 UTCEPSS rescoreEPSS 40% · 98th percentile
  53. 2026-09-08 21:59 UTCEPSS rescoreEPSS 40% · 98th percentile
  54. 2026-09-06 13:46 UTCEPSS rescoreEPSS 40% · 98th percentile
  55. 2026-09-05 15:28 UTCEPSS rescoreEPSS 40% · 98th percentile
  56. 2026-09-04 05:05 UTCEPSS rescoreEPSS 40% · 98th percentile
  57. 2026-09-02 14:11 UTCEPSS rescoreEPSS 40% · 98th percentile
  58. 2026-09-01 04:38 UTCEPSS rescoreEPSS 40% · 98th percentile
  59. 2026-08-30 19:16 UTCEPSS rescoreEPSS 40% · 98th percentile
  60. 2026-08-30 01:21 UTCEPSS rescoreEPSS 40% · 98th percentile
  61. 2026-08-28 21:40 UTCEPSS rescoreEPSS 40% · 98th percentile
  62. 2026-08-27 14:24 UTCEPSS rescoreEPSS 40% · 98th percentile
  63. 2026-08-25 20:39 UTCOSV refresh
  64. 2026-08-25 13:47 UTCEPSS rescoreEPSS 40% · 98th percentile
  65. 2026-08-21 23:48 UTCEPSS rescoreEPSS 40% · 98th percentile
  66. 2026-08-20 22:54 UTCEPSS rescoreEPSS 40% · 98th percentile
  67. 2026-08-19 17:03 UTCEPSS rescoreEPSS 40% · 98th percentile
  68. 2026-08-18 13:47 UTCEPSS rescoreEPSS 40% · 98th percentile
  69. 2026-08-17 13:46 UTCEPSS rescoreEPSS 40% · 98th percentile
  70. 2026-08-16 14:55 UTCEPSS rescoreEPSS 40% · 98th percentile
  71. 2026-08-16 02:13 UTCEPSS rescoreEPSS 40% · 98th percentile

Publicly available exploits

(1 reference)

Public exploit code is referenced for this CVE (1 GitHub PoC). Defenders should treat patch urgency accordingly.

  • GitHub PoCrxerium/CVE-2025-26466
    Published 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 ↗

Frequently asked(5)

What is CVE-2025-26466?
CVE-2025-26466 is a medium-severity vulnerability; its CVE record was 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 made public?
CVE-2025-26466 was made public on February 18, 2025: that is the date its CVE record's CNA, Red Hat, Inc., gives for when the vulnerability was made public. The CVE record itself was published on February 28, 2025. EchelonGraph's copy of the record carries a last-modified date of October 21, 2026; the record at its source may have been updated since.
Is CVE-2025-26466 actively exploited?
CVE-2025-26466 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 39% probability of exploitation in the next 30 days (98th percentile of EPSS-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 + FIRST EPSS + GHSA into a combined EG score of 6.4 (MEDIUM).
How do I remediate CVE-2025-26466?
A fix for CVE-2025-26466 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2025-26466 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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