mm/hugetlb: fix hugetlb cgroup rsvd charge/uncharge mismatch
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- None · High · High
- Fix status
- Partial Red Hat: 4 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
Summary
In the Linux kernel, the following vulnerability has been resolved: mm/hugetlb: fix hugetlb cgroup rsvd charge/uncharge mismatch In alloc_hugetlb_folio(), a single h_cg pointer is used for both the rsvd and non-rsvd hugetlb cgroup charges. When map_chg is set, hugetlb_cgroup_charge_cgroup_rsvd() stores the charged cgroup in h_cg, but the immediately following hugetlb_cgroup_charge_cgroup() overwrites h_cg with the non-rsvd cgroup pointer. As a result, hugetlb_cgroup_commit_charge_rsvd() stores the wrong (non-rsvd) cgroup pointer into the folio's rsvd slot. When the folio is later freed, free_huge_folio() unconditionally calls both hugetlb_cgroup_uncharge_folio() and hugetlb_cgroup_uncharge_folio_rsvd(). The rsvd uncharge reads back the wrong cgroup from the folio and decrements a counter that was never charged for that cgroup, causing a page_counter underflow: page_counter underflow: -512 nr_pages=512 WARNING: mm/page_counter.c:61 at page_counter_cancel Fix this by introducing a separate h_cg_rsvd pointer exclusively for the rsvd charge path, keeping the rsvd and non-rsvd charges fully independent through their charge, commit, and error uncharge paths.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
- Fix · CNA Linux (Linux) Fixed in 6.1.191, 6.6.160, 6.12.101, 6.18.40, 7.1.5, 7.2
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
Not affected: 1 product
- Red Hat Enterprise Linux 7
Timeline
- 2026-10-02 Threatist record created from CVE-2026-72213
- 2026-10-03 Alias added: GHSA-cqhp-gwhx-vmwp
- 2026-10-16 CISA SSVC decision points changed
- 2026-10-21 Fix available: Linux/Linux@043c509f2488033c68c46d2de2af082fcd568612, Linux/[email protected] · CNA
- 2026-10-21 1 new reference · CNA
- 2026-10-30 Fix available: Linux/[email protected], Linux/Linux@f8dfdf725bccb0ae41eead2f6da8183727218855 · CNA
- 2026-10-30 1 new reference · CNA
- 2026-11-03 CVSS score changed · Red Hat
References
Other 6
- https://git.kernel.org/stable/c/f8dfdf725bccb0ae41eead2f6da8183727218855
- https://git.kernel.org/stable/c/043c509f2488033c68c46d2de2af082fcd568612
- https://git.kernel.org/stable/c/5c32ae4a91fb5f4941328e0c1720a7fa4189c3bd
- https://git.kernel.org/stable/c/1697d253f51cf5e3825a3423ff49e128a3502ab2
- https://git.kernel.org/stable/c/b785f2bd9496facedc0a031be09cddcd1d3c84d3
- https://git.kernel.org/stable/c/15807d0ddde37407af72859426b654f3d1972b00
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Sources
- CVE-2026-72213 · CVE Program
- CVE-2026-72213 · NVD
- FIRST EPSS
- GHSA-cqhp-gwhx-vmwp · GitHub Advisory Database · CC BY 4.0
- CVE-2026-72213 · 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