CVE-2026-89664

HIGHPre-NVD 7.57.5
EchelonGraph scoreMEDIUM confidence

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

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-09-11. A secondary CVSS source baseline 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, a secondary CVSS source
Trending — 3 sources updated this week
7.5EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.5%CVSS: 7.5Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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

nfsd: release OPEN-decoded posix ACLs via op_release

nfsd4_decode_createhow4() calls nfsd4_decode_fattr4(), which allocates refcounted struct posix_acl objects via posix_acl_alloc() and stores them in open->op_pacl and open->op_dpacl. These pointers must be released once the OPEN compound finishes.

When nfsd4_decode_open_claim4() returns a non-seqid-mutating error, the dispatcher short-circuits before op_func runs:

nfsd4_proc_compound() if (op->status && op->opnum == OP_OPEN) op->status = nfsd4_open_omfg(...) if (!seqid_mutating_err(ntohl(op->status))) return op->status; /* nfsd4_open() never runs */ ... opdesc->op_release(&op->u) /* must still release op_pacl/op_dpacl */

Before this change OP_OPEN had no .op_release in nfsd4_ops[], and the release pair lived inside nfsd4_open() at its out_err: label. On the short-circuit path nfsd4_open() is never invoked, so both posix_acl refs leak on every malformed OPEN compound that carries valid POSIX ACL createhow4 attributes.

Add nfsd4_open_release() and wire it as .op_release for OP_OPEN. posix_acl_release() is NULL-safe, so the single release site covers both the normal path and the nfsd4_open_omfg short-circuit. Remove the matching posix_acl_release() pair from nfsd4_open()'s out_err: label to avoid double-releasing.

The compound loop has two encoding branches: nfsd4_encode_operation() for normal ops, and nfsd4_encode_replay() for v4.0 replayed ops. op_release was only called from nfsd4_encode_operation(), so resources attached to op->u leak on the replay path.

Move the op_release() call out of nfsd4_encode_operation() and the replay branch, placing it after the if-else in nfsd4_proc_compound(). This gives a single call site in a fairly obviously-correct place, covering both the normal encoding and replay paths.

CVSS v3
7.5
EG Score
7.5HIGHmedium confidence
EG Risk
34
EG Risk 34/100

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 (value × EchelonGraph’s weight)
Severity75% × 45%
The EG Score, 7.5 of 10.
Exploitation0.5% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
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 or medium mission impact; Track* at high (mission-essential systems).
Exploitation none (no CISA value, KEV listing or 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.
EPSS PROB
0.5%
EPSS %ILE
40th
KEV
Not listed

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 none (no CISA value, KEV listing or 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.

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

September 11, 2026

Last Modified

September 13, 2026

Advisory Details (2)

Auto-updated Sep 13, 2026
Patch available.
Web page

nfsd: release OPEN-decoded posix ACLs via op_release - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/8215892993ea9f5231da4fa9eb42428a286fce8b
Web page

nfsd: release OPEN-decoded posix ACLs via op_release - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/5b3a7d7c23c071efe12dd1bc1d2e5f97c4892921

Vendor Advisories for CVE-2026-89664(1)

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

Affected Packages

(1 across 1 ecosystem)
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.12.100-1 ... 7.2~rc7-1~exp1 (178 versions)
  • every version up to 7.2.6-1: fixed in 7.2.6-1
—

Data Freshness Timeline

(refreshed 26× in last 7d / 110× 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 99 of 123 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. 1 repeat row among the latest 100 is merged into the row it repeats. The 24 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  2. 2026-10-13 04:53 UTCEG score recompute
  3. 2026-10-13 04:53 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  4. 2026-10-12 16:35 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  5. 2026-10-12 14:48 UTCEG score recompute
  6. 2026-10-11 22:46 UTCEG score recompute
  7. 2026-10-11 22:46 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  8. 2026-10-11 19:15 UTCEG score recompute
  9. 2026-10-11 16:31 UTCEG score recompute
  10. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  11. 2026-10-11 13:47 UTCEG score recompute
  12. 2026-10-11 09:45 UTCEG score recompute
  13. 2026-10-11 09:45 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  14. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  15. 2026-10-10 18:37 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  16. 2026-10-10 05:36 UTCEG score recompute
  17. 2026-10-10 05:36 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  18. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  19. 2026-10-09 16:30 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  20. 2026-10-09 01:35 UTCEG score recompute
  21. 2026-10-09 01:34 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  22. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  23. 2026-10-08 12:34 UTCEG score recompute
  24. 2026-10-08 12:34 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  25. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.5% · 40th percentile
Show 74 more
  1. 2026-10-07 22:26 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  2. 2026-10-07 09:11 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  3. 2026-10-06 20:10 UTCEG score recompute
  4. 2026-10-06 20:10 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  5. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  6. 2026-10-06 07:10 UTCEG score recompute
  7. 2026-10-06 07:10 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  8. 2026-10-05 17:44 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  9. 2026-10-05 17:27 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  10. 2026-10-05 04:28 UTCEG score recompute
  11. 2026-10-05 04:28 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  12. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  13. 2026-10-04 15:27 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  14. 2026-10-04 02:07 UTCEG score recompute
  15. 2026-10-04 02:07 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  16. 2026-10-03 13:07 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  17. 2026-10-03 00:06 UTCEG score recompute
  18. 2026-10-03 00:06 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  19. 2026-10-02 10:06 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  20. 2026-10-01 21:06 UTCEG score recompute
  21. 2026-10-01 21:06 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  22. 2026-10-01 19:51 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  23. 2026-10-01 08:05 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  24. 2026-09-30 19:05 UTCEG score recompute
  25. 2026-09-30 19:05 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  26. 2026-09-30 15:04 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  27. 2026-09-30 06:05 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  28. 2026-09-29 17:05 UTCEG score recompute
  29. 2026-09-29 17:04 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  30. 2026-09-29 03:42 UTCEG score recompute
  31. 2026-09-29 03:42 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  32. 2026-09-28 14:39 UTCEG score recompute
  33. 2026-09-28 14:39 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  34. 2026-09-28 13:52 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  35. 2026-09-28 01:39 UTCEG score recompute
  36. 2026-09-28 01:39 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  37. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  38. 2026-09-27 12:36 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  39. 2026-09-26 23:36 UTCEG score recompute
  40. 2026-09-26 23:35 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  41. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  42. 2026-09-26 10:10 UTCEG score recompute
  43. 2026-09-26 10:10 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  44. 2026-09-25 21:03 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  45. 2026-09-25 05:59 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  46. 2026-09-24 16:59 UTCEG score recompute
  47. 2026-09-24 16:59 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  48. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  49. 2026-09-24 03:59 UTCEG score recompute
  50. 2026-09-24 03:59 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  51. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  52. 2026-09-23 14:58 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  53. 2026-09-23 01:58 UTCEG score recompute
  54. 2026-09-23 01:58 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  55. 2026-09-22 16:01 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  56. 2026-09-22 12:58 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  57. 2026-09-21 23:58 UTCEG score recompute
  58. 2026-09-21 23:57 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  59. 2026-09-21 21:09 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  60. 2026-09-21 10:57 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  61. 2026-09-20 21:56 UTCEG score recompute
  62. 2026-09-20 21:56 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  63. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  64. 2026-09-20 08:55 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  65. 2026-09-19 19:55 UTCEG score recompute
  66. 2026-09-19 19:54 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  67. 2026-09-19 06:53 UTCEG score recompute
  68. 2026-09-19 06:53 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  69. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  70. 2026-09-18 17:53 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  71. 2026-09-18 04:53 UTCEG score recompute
  72. 2026-09-18 04:53 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  73. 2026-09-17 19:32 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  74. 2026-09-17 15:53 UTCGHSA enrichmentGHSA-2mmp-54r9-hmh2 · GitHub severity HIGH · GitHub CVSS 7.5

Frequently asked(5)

What is CVE-2026-89664?
CVE-2026-89664 is a high-severity vulnerability; its CVE record was published on September 11, 2026. In the Linux kernel, the following vulnerability has been resolved: nfsd: release OPEN-decoded posix ACLs via op_release nfsd4decodecreatehow4() calls nfsd4decodefattr4(), which allocates refcounted struct posixacl objects via posixacl_alloc() and stores them in open->oppacl and open->opdpacl.…
When was the CVE record for CVE-2026-89664 published?
The CVE record for CVE-2026-89664 was published on September 11, 2026. 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 September 13, 2026; the record at its source may have been updated since.
Is CVE-2026-89664 actively exploited?
CVE-2026-89664 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.5% probability of exploitation in the next 30 days (40th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-89664?
CVE-2026-89664 has a CVSS base score of 7.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-89664?
A fix for CVE-2026-89664 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-89664 are linked in the Vendor Advisories panel on this page.

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