CVE Intelligence
High

CVE-2026-89705 — nfsd: restore rq_status_counter to even on all nfsd_dispatch() exit paths

In the Linux kernel, the following vulnerability has been resolved: nfsd: restore rq_status_counter to even on all nfsd_dispatch() exit paths nfsd_dispatch() sets rq_status_counter to an odd value once a request has been decoded, and back to an even value once it has been fully processed, forming a seq-lock like protocol with the lockless reader in nfsd_nl_rpc_status_get_dumpit(). Only the fully successful path restored the counter to even. The cache-hit (RC_REPLY), drop (RC_DROPIT / RQ_DROPME) and encode-error paths all return after the odd-valued store without ever bringing the counter back to even. Once one of those paths is taken, rq_status_counter is left odd: the next request's decode ORs in 1 (still odd) and only a subsequent successful encode restores even. While stuck odd, the dumpit reader treats the rqstp fields as stable and its retry check compares against the same unchanging odd value, so it never detects concurrent mutation. This exposes actively mutating fields (e.g. args->ops / args->opcnt during compound decode and release) to the lockless reader, which can read past the end of the 8-element inline ops array. Add a helper that advances the counter to the next even value and call it on every return path that follows the odd-valued store. The decode-error path is left untouched as it is reached before the counter is set odd.

Published Sep 11, 2026 · Updated Oct 15, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · CNA: Linux

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 0.2% (30-day exploitation probability)+1
  • Technical severity (high)+6

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
0.16%
ahead of 4% of scored CVEs · Oct 14, 2026
Affects
Linux
Linux
CVSS base
7.1
High · 3 source(s)

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Linux Linux).
  2. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  3. Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Linux Linux ≥ bd9d6a3efa9709e653aafbeb859289feccb8e70c and < df5500ab85df661d9e4439e4c456787181fbd5ff≥ bd9d6a3efa9709e653aafbeb859289feccb8e70c and < b08c30f08d57f30699d36809d92f0b683dca261f≥ bd9d6a3efa9709e653aafbeb859289feccb8e70c and < f6045886fe3f14f269f683d64021b004a50d0efaversion 6.7 Vulnerable CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
7.1 CVSS 3.1 High 1.8 5.2 416baaa9-dc9f-4396-8d5f-8c081fb06d67 via NIST National Vulnerability Database
7.1 CVSS 3.1 High — — GitHub, Inc. via GitHub Security Advisories
7.1 CVSS 3.1 High — — Linux via CVE Program (cve.org) e CISA ADP
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H (score shown at the top: 416baaa9-dc9f-4396-8d5f-8c081fb06d67)

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
endpoint telemetry (EDR)

Timeline

What happened to this CVE, newest first.

  • 2026
  • Affected products added · linux/linux
    Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 15, 2026
  • CVSS changed · 7.1
    Oct 15, 2026 · NIST National Vulnerability Database
  • Source status changed · → Received
    Oct 15, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 15, 2026 · Alertas do Telegram
  • CVE published
    Sep 11, 2026 · Linux

Source activity

Repeated readings are counted rather than listed.

  • 2× References added · Oct 15, 2026 – Oct 15, 2026
  • 1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

5 on the record

Elsewhere on this site

Linux
every CVE for this vendor

Related CVEs (same products)

  • CVE-2026-99999 ipv4: validate checksum_start before completing checksum 6h
  • CVE-2026-98432 ipv4: free inet_opt and ireq_opt after an RCU grace period 6h
  • CVE-2026-98424 wifi: cfg80211: undo netns switch if renaming the wiphy fails 1d
  • CVE-2026-98425 wifi: mac80211: don't warn when an IBSS has no channel to scan 1d
  • CVE-2026-98426 wifi: mwifiex: fix IRQ leak using wrong index in MSI-X error path 1d
  • CVE-2026-98427 net/sched: codel: bound the dropping loop per dequeue call 1d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No fixed version, patch or mitigation documented.
  • No CISA SSVC assessment.
  • No CWE classification.
  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-89705 is "nfsd: restore rq_status_counter to even on all nfsd_dispatch() exit paths", rated High. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.1 describes technical severity. EPSS 0.16% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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