CVE-2026-98234 (GCVE-0-2026-98234)

Vulnerability from cvelistv5 – Published: 2026-10-06 08:45 – Updated: 2026-10-06 08:45
VLAI
Title
net/sched: hhf: cap hh_flows_limit at change time
Summary
In the Linux kernel, the following vulnerability has been resolved: net/sched: hhf: cap hh_flows_limit at change time hhf_change() stores TCA_HHF_HH_FLOWS_LIMIT with no upper bound. A huge hh_flows_limit lets each new heavy-hitter flow pass the hh_flows_current_cnt check in alloc_new_hh() and forces a fixed-size kzalloc(GFP_ATOMIC) per flow under spoofed traffic, for unbounded memory growth. Bound the attribute with NLA_POLICY_MAX() at 2*HH_FLOWS_CNT (the hhf_init() default) and report the rejected value via extack. The deprecated nested parse is kept: legacy tc does not set NLA_F_NESTED on TCA_OPTIONS. Configs relying on hh_limit above the default were relying on unbounded, unsafe behaviour and are not supported going forward. hhf_init() also ran hhf_change() before setting the default hh_flows_limit, so a user-supplied hh_limit at add time was clobbered back to 2048. Set the default before hhf_change() so the configured value sticks. This is a follow-up to commit eb56a495f59b ("net/sched: hhf: clamp quantum in change and init paths"), which bounded the quantum of the same qdisc; the hh_flows_limit bound is the remaining unbounded knob of that series' scope. Conditions to recreate the bug: CAP_NET_ADMIN in a user namespace; tc qdisc change dev X root hhf hh_limit 4294967295 succeeds and the value is echoed by tc qdisc show, unbounding heavy-hitter flow allocations; also tc qdisc add dev X root hhf hh_limit 500 stores 2048 instead of 500.
Severity
No CVSS data available.
Assigner
Linux CNA under the mitre root
CNA scorecard D 54/100 over 6633 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 10239edf86f137ce4c39b62ea9575e8053c549a0 , < 7adfd0a42174b85c6bd678858ecd6674f403f336 (git)
Affected: 10239edf86f137ce4c39b62ea9575e8053c549a0 , < 35fd423a5c5132c6f4321f6c4f0a7b4b90af830c (git)
Affected: 10239edf86f137ce4c39b62ea9575e8053c549a0 , < 06d2a101e89063cb0b9b459104db48bdfb0a797d (git)
Affected: 10239edf86f137ce4c39b62ea9575e8053c549a0 , < d8e2f1f0263b7c97b222c06070cccf13e0ab7112 (git)
Affected: 10239edf86f137ce4c39b62ea9575e8053c549a0 , < f3f4a5cb4a6e9b1f1f25d34dfc25f836a1601db4 (git)
Affected: 10239edf86f137ce4c39b62ea9575e8053c549a0 , < 1731ff1d20489afe4cd01b7d16d37f324746ac54 (git)
Affected: 10239edf86f137ce4c39b62ea9575e8053c549a0 , < f6547d27ce2093c5627636fb63dd0b7523c466f9 (git)
Affected: 10239edf86f137ce4c39b62ea9575e8053c549a0 , < 2cef2588c995722a901368def30befeef9ae55c6 (git)
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Linux Linux Affected: 3.14
Unaffected: 0 , < 3.14 (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: 6.18.54 , ≤ 6.18.* (semver)
Unaffected: 7.2.8 , ≤ 7.2.* (semver)
Unaffected: 7.3-rc4 , ≤ * (original_commit_for_fix)
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      "product_status:known_affected": "49",
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      "source": "Red Hat CSAF VEX",
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      "title": "kernel: net/sched: hhf: cap hh_flows_limit at change time",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98234.json",
      "version": "3"
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      "cve": "CVE-2026-98234",
      "id": "CVE-2026-98234",
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      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-98234",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-98234.json",
      "version": "2"
    }
  }
}



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Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • 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.



Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.