CVE-2025-37899

HIGHNVD 7.87.8
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to NVD's CVSS score.

Score 7.8 from GitHub Security Advisory (severity: HIGH) published 2025-05-20. NVD baseline CVSS 7.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, NVD CVSS v3
Trending — 4 sources updated this weekElevated

Also known asEUVD-2025-15946 (ENISA EUVD) · GHSA-3rcg-456g-86p6 (GitHub Security Advisories)Source: ENISA EUVD

7.8EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • Public exploit or proof-of-concept code is available
CISA-KEV: Not listedEPSS PROB: 0.9%CVSS: 7.8Exploit: Public PoCExposed services: Not assessed

A fix is available — apply it.

In the Linux kernel, the following vulnerability has been resolved:

ksmbd: fix use-after-free in session logoff

The sess->user object can currently be in use by another thread, for example if another connection has sent a session setup request to bind to the session being free'd. The handler for that connection could be in the smb2_sess_setup function which makes use of sess->user.

CVSS v3
7.8
EG Score
7.8HIGHmedium confidence
EG Risk
51
EG Risk 51/100

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)
Severity78% × 45%
Impact severity (EG Severity): CVSS 7.8 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 BOD 26-04 default: no one has published Automatable for this CVE, and CISA treats it as “no” for a CVE not in KEV.
SSVC (CISA's decision table, applied by EchelonGraph): Track at low, Track* at medium and Attend at high mission impact.
Exploitation public PoC (exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from 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 at low or medium mission impact and sooner than that at high.
EPSS PROB
0.9%
EPSS %ILE
59th
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 (7.8): severity, escalated by confirmed exploitation. This CVE's 7.8 is its impact severity (EG Severity), not escalated.

EG Severity
7.8 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.9% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-27). 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, Track* at medium and Attend at high mission impact.CISA BOD 26-04: 14 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, Track* at medium and Attend at high mission impact.

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation public PoC (exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from 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)14 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's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). Where an input reads “CISA's BOD 26-04 default”, no one has published it for this CVE, and CISA's implementation guidance says: “If “Automatable” and “Technical Impact” information items about a CVE ID are not available and the CVE ID is not in the KEV Catalog, CISA will treat its values as “no” and “total,” respectively, until CISA or a third party provides metadata about the CVE ID. CISA will always provide the Vulnrichment data for a CVE ID listed in the KEV Catalog.” 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

May 20, 2025

Last Modified

August 5, 2026

Advisory Details (7)

Auto-updated Jul 30, 2026
Patch available.
Web page

How I used o3 to find CVE-2025-37899, a remote zeroday vulnerability in the Linux kernel’s SMB implementation – Sean Heelan's Blog

https://sean.heelan.io/2025/05/22/how-i-used-o3-to-find-cve-2025-37899-a-remote-zeroday-vulnerability-in-the-linux-kernels-smb-implementation/
Web page

I used o3 to find a remote zeroday in the Linux SMB implementation | Hacker News

https://news.ycombinator.com/item?id=44081338
Web page

ksmbd: fix use-after-free in session logoff - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/d5ec1d79509b3ee01de02c236f096bc050221b7f
Web page

ksmbd: fix use-after-free in session logoff - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/931dc8a3670f71c45c0b1379ea4e92dafbda1aca
Web page

ksmbd: fix use-after-free in session logoff - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/70ad6455139e26e85f48f95d0e21f351c1909342
Web page

ksmbd: fix use-after-free in session logoff - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/2fc9feff45d92a92cd5f96487655d5be23fb7e2b
Web page

ksmbd: fix use-after-free in session logoff - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/02d16046cd11a5c037b28c12ffb818c56dd3ef43

Vendor Advisories for CVE-2025-37899(1)

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

Patch Availability(18)

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

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
linux-6.16.1.106-3~deb11u1 ... 6.1.158-1~deb11u1 (13 versions)
  • every version up to 6.1.159-1~deb11u1: fixed in 6.1.159-1~deb11u1
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.1.106-1 ... 6.1.99-1 (45 versions)
  • every version up to 6.1.159-1: fixed in 6.1.159-1
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
linux—
  • every version up to 6.12.29-1: fixed in 6.12.29-1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
linux—
  • every version up to 6.12.29-1: fixed in 6.12.29-1
—

Weakness Classification(1)

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

Additional Vendor Advisories

(17)

Data Freshness Timeline

(refreshed 10× in last 7d / 42× 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 98 of 198 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. 2 repeat rows among the latest 100 are merged into the row they repeat. The 100 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-02 16:42 UTCEPSS rescoreEPSS 0.9% · 59th percentile
  2. 2026-11-01 16:32 UTCEPSS rescoreEPSS 0.9% · 59th percentile
  3. 2026-10-31 16:31 UTCEPSS rescoreEPSS 0.9% · 59th percentile
  4. 2026-10-30 16:32 UTCEPSS rescoreEPSS 0.9% · 59th percentile
  5. 2026-10-29 16:31 UTCEPSS rescoreEPSS 0.9% · 59th percentile
  6. 2026-10-28 16:30 UTCEPSS rescoreEPSS 0.9% · 59th percentile
  7. 2026-10-27 17:40 UTCEG score recompute
  8. 2026-10-27 17:40 UTCVendor advisory
  9. 2026-10-27 17:40 UTCGHSA enrichmentGHSA-3rcg-456g-86p6 · GitHub severity HIGH · GitHub CVSS 7.8
  10. 2026-10-27 16:30 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  11. 2026-10-26 16:30 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  12. 2026-10-25 16:31 UTCEG score recompute
  13. 2026-10-25 16:31 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  14. 2026-10-24 16:31 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  15. 2026-10-23 16:30 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  16. 2026-10-22 16:33 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  17. 2026-10-21 16:31 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  18. 2026-10-20 16:31 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  19. 2026-10-19 16:30 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  20. 2026-10-18 17:02 UTCEG score recompute
  21. 2026-10-18 17:02 UTCVendor advisory
  22. 2026-10-18 17:02 UTCGHSA enrichmentGHSA-3rcg-456g-86p6 · GitHub severity HIGH · GitHub CVSS 7.8
  23. 2026-10-18 16:30 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  24. 2026-10-18 05:36 UTCEG score recompute
  25. 2026-10-17 16:33 UTCEPSS rescoreEPSS 0.9% · 58th percentile
Show 73 more
  1. 2026-10-16 16:38 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  2. 2026-10-15 16:30 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  3. 2026-10-14 16:31 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  4. 2026-10-13 16:32 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  5. 2026-10-12 17:08 UTCEG score recompute
  6. 2026-10-12 16:33 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  7. 2026-10-11 20:41 UTCEG score recompute
  8. 2026-10-11 18:51 UTCEG score recompute
  9. 2026-10-11 15:28 UTCEG score recompute
  10. 2026-10-11 13:47 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  11. 2026-10-10 19:59 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  12. 2026-10-09 20:06 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  13. 2026-10-08 17:09 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  14. 2026-10-07 23:46 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  15. 2026-10-06 15:16 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  16. 2026-10-05 17:42 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  17. 2026-10-04 23:21 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  18. 2026-10-03 14:24 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  19. 2026-10-01 19:49 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  20. 2026-09-30 15:02 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  21. 2026-09-28 13:50 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  22. 2026-09-27 03:15 UTCOSV refresh
  23. 2026-09-26 15:58 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  24. 2026-09-26 00:24 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  25. 2026-09-24 14:02 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  26. 2026-09-23 13:47 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  27. 2026-09-20 20:15 UTCEPSS rescoreEPSS 1.0% · 60th percentile
  28. 2026-09-18 19:27 UTCEPSS rescoreEPSS 1.0% · 60th percentile
  29. 2026-09-17 19:29 UTCEPSS rescoreEPSS 1.0% · 60th percentile
  30. 2026-09-16 14:07 UTCEPSS rescoreEPSS 1.0% · 60th percentile
  31. 2026-09-16 05:14 UTCEPSS rescoreEPSS 1.0% · 60th percentile
  32. 2026-09-13 16:46 UTCEPSS rescoreEPSS 1.0% · 60th percentile
  33. 2026-09-12 15:00 UTCEPSS rescoreEPSS 1.0% · 60th percentile
  34. 2026-09-11 14:52 UTCEPSS rescoreEPSS 1.0% · 60th percentile
  35. 2026-09-11 09:35 UTCEPSS rescoreEPSS 1.0% · 60th percentile
  36. 2026-09-10 09:33 UTCEPSS rescoreEPSS 1.0% · 60th percentile
  37. 2026-09-08 21:59 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  38. 2026-09-07 16:00 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  39. 2026-09-07 12:47 UTCOSV refresh
  40. 2026-09-06 13:46 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  41. 2026-09-04 05:05 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  42. 2026-09-02 14:11 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  43. 2026-09-01 13:53 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  44. 2026-09-01 04:38 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  45. 2026-08-30 19:16 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  46. 2026-08-30 01:21 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  47. 2026-08-28 21:40 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  48. 2026-08-27 14:24 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  49. 2026-08-26 14:45 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  50. 2026-08-25 13:48 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  51. 2026-08-23 00:18 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  52. 2026-08-21 23:48 UTCEPSS rescoreEPSS 1.0% · 59th percentile
  53. 2026-08-20 22:54 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  54. 2026-08-20 22:01 UTCOSV refresh
  55. 2026-08-19 17:03 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  56. 2026-08-18 13:47 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  57. 2026-08-16 14:55 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  58. 2026-08-16 02:13 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  59. 2026-08-15 01:29 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  60. 2026-08-13 21:59 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  61. 2026-08-12 13:50 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  62. 2026-08-09 13:46 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  63. 2026-08-08 16:36 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  64. 2026-08-07 16:26 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  65. 2026-08-06 13:46 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  66. 2026-08-05 13:55 UTCEG score recompute
  67. 2026-08-05 13:55 UTCVendor advisory
  68. 2026-08-05 13:55 UTCGHSA enrichmentGHSA-3rcg-456g-86p6 · GitHub severity HIGH · GitHub CVSS 7.8
  69. 2026-08-04 15:09 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  70. 2026-08-04 10:37 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  71. 2026-08-03 10:35 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  72. 2026-08-02 02:26 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  73. 2026-08-01 04:15 UTCEPSS rescoreEPSS 0.9% · 57th percentile

Publicly available exploits

(1 reference)

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

  • GitHub PoCSeanHeelan/o3_finds_cve-2025-37899
    Published May 22, 2025

    Artefacts for blog post on finding CVE-2025-37899 with o3

    Open source ↗

Frequently asked(5)

What is CVE-2025-37899?
CVE-2025-37899 is a high-severity vulnerability; its CVE record was published on May 20, 2025. In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix use-after-free in session logoff The sess->user object can currently be in use by another thread, for example if another connection has sent a session setup request to bind to the session being free'd. The handler for…
When was the CVE record for CVE-2025-37899 published?
The CVE record for CVE-2025-37899 was published on May 20, 2025. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of August 5, 2026; the record at its source may have been updated since.
Is CVE-2025-37899 actively exploited?
CVE-2025-37899 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.9% probability of exploitation in the next 30 days (59th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2025-37899?
CVE-2025-37899 has a CVSS v3 base score of 7.8 (NVD).
How do I remediate CVE-2025-37899?
A fix for CVE-2025-37899 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2025-37899 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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