Unbounded cache growth in Linux kernel ipvs LBLC and LBLCR
Key facts
- Attack vector
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- Privileges required
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- User interaction
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- Attack complexity
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- Impact type
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- Confidentiality · integrity · availability
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- Fix status
- Partial Red Hat: 7 without a fix
No CVSS vector from any source. Fix status from CNA and Red Hat.
Summary
The Linux kernel IPVS LBLC and LBLCR schedulers create a cache entry for every previously unseen destination address. An attacker who sends traffic to many distinct destination addresses can grow these cache tables beyond their max_size, because the periodic collector reclaims entries only after the limit is already exceeded.
Written with Claude Haiku 5.5 from the sources below · 2026-10-30
Description from the CNA
In the Linux kernel, the following vulnerability has been resolved: ipvs: bound LBLCR and LBLC cache growth ip_vs_lblcr_new() and ip_vs_lblc_new() create cache entries for every previously unseen destination address. The table max_size only tells the periodic collector to reclaim entries after the cache has already exceeded the limit. It does not reclaim entries that the attacker continues to use. Reject new cache entries once either table reaches max_size * 3 / 2. The extra headroom lets the periodic collector catch up while the existing scheduler fallback continues to use the selected destination when cache creation fails. New traffic therefore stays serviceable without growing the tables further.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 2.6.12 and later | 5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.113, 6.18.56, 7.2.10, 7.3 | Patch available | CNA |
- Linux VendorLinux Affected 2.6.12 and later Fixed in 5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.113, 6.18.56, 7.2.10, 7.3 Patch available CNA
Remediation
Upgrade the Linux kernel to a fixed stable release: 5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.113, 6.18.56, 7.2.10 or 7.3. Red Hat gives no fix plan for Red Hat Enterprise Linux 6, 7, 8, 9 and 10 or for OpenShift Container Platform 4 and 5.
Written with Claude Haiku 5.5 from the sources below · 2026-10-30
- Fix · CNA Linux (Linux) Fixed in 5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.113, 6.18.56, 7.2.10, 7.3
Vendor assessments
Red Hat
Red Hat rating: Important. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet |
| Red Hat Enterprise Linux 6 | Affected | No fix yet |
| Red Hat Enterprise Linux 7 | Affected | No fix yet |
| Red Hat Enterprise Linux 8 | Affected | No fix yet |
| Red Hat Enterprise Linux 9 | Affected | No fix yet |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet |
Timeline
- 2026-10-18 Threatist record created from CVE-2026-98857
- 2026-10-18 Alias added: GHSA-3qgh-gjj6-qj8r
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-10-21 Fix available: Linux/[email protected], Linux/Linux@bc9ff8e64771cc32a216953fe615386f46ac1eaa · CNA
- 2026-10-21 1 new reference · CNA
- 2026-10-24 Affected versions changed · Red Hat
- 2026-10-24 CVSS score added · Red Hat
- 2026-10-30 Affected versions changed · Red Hat
- 2026-10-30 Fix available: Linux/Linux@488eaba207dd2e4c5afc65e18dc237d70f01d283, Linux/[email protected], Linux/[email protected] +3 · CNA
- 2026-10-30 3 new references · CNA
References
Other 8
- https://git.kernel.org/stable/c/8b93288b4543ad5139a25a5b211a07bf755652dd
- https://git.kernel.org/stable/c/f6e9446bfb79907d3092fc45a0054b0c3b329bfe
- https://git.kernel.org/stable/c/488eaba207dd2e4c5afc65e18dc237d70f01d283
- https://git.kernel.org/stable/c/bc9ff8e64771cc32a216953fe615386f46ac1eaa
- https://git.kernel.org/stable/c/31028d7b970962fbeda1e9131405c76551094300
- https://git.kernel.org/stable/c/6316d17324bd4ca400c26adb7b656c6e3447c209
- https://git.kernel.org/stable/c/16c83c047ecfaf226ad81d45d77fa11a3184d0e4
- https://git.kernel.org/stable/c/2a3c3de660f96865f303fd25f1285f2ffbfd521d
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Sources
- CVE-2026-98857 · CVE Program
- CVE-2026-98857 · NVD
- FIRST EPSS
- GHSA-3qgh-gjj6-qj8r · GitHub Advisory Database · CC BY 4.0
- CVE-2026-98857 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences