CVE-2026-98622 (GCVE-0-2026-98622)

Vulnerability from cvelistv5 – Published: 2026-10-18 15:19 – Updated: 2026-10-19 09:22
VLAI
Title
net/sched: act_ct: don't WARN on benign flow_offload_alloc() failure
Summary
In the Linux kernel, the following vulnerability has been resolved: net/sched: act_ct: don't WARN on benign flow_offload_alloc() failure flow_offload_alloc() returns NULL when the conntrack entry is dying (e.g. raced with a conntrack flush) or when the GFP_ATOMIC allocation fails; both are expected under load and neither is a kernel bug. This path runs from softirq on every committed packet, so with panic_on_warn=1 an unprivileged user can panic the box just by racing a conntrack flush against a `tc ... action ct commit` classifier. Reproduced with a custom repro under QEMU: a small, fixed set of UDP flows through `tc filter ... action ct commit` on lo, raced against threads flooding bare ctnetlink CT_DELETE (flush) requests. Hits WARNING: net/sched/act_ct.c:437 (tcf_ct_flow_table_add(), inlined into tcf_ct_act() in this build) within ~15s on the unpatched kernel; same setup is clean on the patched kernel. The fix itself is behavior-preserving: both branches already did `goto err_alloc` before and after, only the WARN is removed.
Severity
No CVSS data available.
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 6640 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 64ff70b80fd403110b67dd9f7184a604fdb0da43 , < e8fcf3f08834e939b797311742ee72b1e2a08096 (git)
Affected: 64ff70b80fd403110b67dd9f7184a604fdb0da43 , < af475f599270e59313552e6c6f3af8507da672b8 (git)
Affected: 64ff70b80fd403110b67dd9f7184a604fdb0da43 , < 424ba52c0058deeb940d02cba52eb0aeb288db33 (git)
Affected: 64ff70b80fd403110b67dd9f7184a604fdb0da43 , < d512c484bd93a5f2794aa03c9faeb7bcb82dbd4a (git)
Affected: 64ff70b80fd403110b67dd9f7184a604fdb0da43 , < d805560ad69cb266d669341ca01e26bffb0d2c67 (git)
Affected: 64ff70b80fd403110b67dd9f7184a604fdb0da43 , < 00734f3684fcec42c319bedfe68a5d357c720b53 (git)
Affected: 64ff70b80fd403110b67dd9f7184a604fdb0da43 , < 650787233c2fd6e515a7c5f371019a9fa080ccd2 (git)
Affected: 64ff70b80fd403110b67dd9f7184a604fdb0da43 , < 47abe7a5c4eb53269aca3506446f851572a059a3 (git)
guessed Create a notification for this product.
Linux Linux Affected: 5.7
Unaffected: 0 , < 5.7 (semver)
Unaffected: 5.10.271 , ≤ 5.10.* (semver)
Unaffected: 5.15.222 , ≤ 5.15.* (semver)
Unaffected: 6.1.189 , ≤ 6.1.* (semver)
Unaffected: 6.6.158 , ≤ 6.6.* (semver)
Unaffected: 6.12.112 , ≤ 6.12.* (semver)
Unaffected: 6.18.55 , ≤ 6.18.* (semver)
Unaffected: 7.2.9 , ≤ 7.2.* (semver)
Unaffected: 7.3 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: act_ct: don\u0027t WARN on benign flow_offload_alloc() failure\n\nflow_offload_alloc() returns NULL when the conntrack entry is dying\n(e.g. raced with a conntrack flush) or when the GFP_ATOMIC allocation\nfails; both are expected under load and neither is a kernel bug. This\npath runs from softirq on every committed packet, so with\npanic_on_warn=1 an unprivileged user can panic the box just by racing\na conntrack flush against a `tc ... action ct commit` classifier.\n\nReproduced with a custom repro under QEMU: a small, fixed set of UDP\nflows through `tc filter ... action ct commit` on lo, raced against\nthreads flooding bare ctnetlink CT_DELETE (flush) requests. Hits\nWARNING: net/sched/act_ct.c:437 (tcf_ct_flow_table_add(), inlined\ninto tcf_ct_act() in this build) within ~15s on the unpatched kernel;\nsame setup is clean on the patched kernel. The fix itself is\nbehavior-preserving: both branches already did `goto err_alloc`\nbefore and after, only the WARN is removed."
        }
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      "providerMetadata": {
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        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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    "dateReserved": "2026-09-25T10:25:14.360Z",
    "dateUpdated": "2026-10-19T09:22:50.359Z",
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          }
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        "id": "CVE-2026-98622",
        "lastModified": "2026-10-19T10:19:26.330",
        "metrics": {},
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        "vulnStatus": "Received"
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      "current_release_date": "2026-11-06T03:05:07+00:00",
      "cve": "CVE-2026-98622",
      "id": "CVE-2026-98622",
      "initial_release_date": "2026-10-18T00:00:00+00:00",
      "product_status:known_affected": "161",
      "product_status:known_not_affected": "42",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: net/sched: act_ct: don\u0027t WARN on benign flow_offload_alloc() failure",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98622.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-10-19T23:49:08Z",
      "cve": "CVE-2026-98622",
      "id": "CVE-2026-98622",
      "initial_release_date": "2026-10-18T23:44:34Z",
      "product_status:known_affected": "231",
      "product_status:known_not_affected": "117",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-98622",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/2026/cve-2026-98622.json",
      "version": "3"
    }
  }
}



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  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

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How durations are calculated

Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.

Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.

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