Linux kernel isofs hits BUG on block sizes above page size
Key facts
- Attack vector
- —
- Privileges required
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- User interaction
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- Attack complexity
- —
- Impact type
- —
- Confidentiality · integrity · availability
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- Fix status
- Partial Red Hat: 1 without a fix
No CVSS vector from any source. Fix status from CNA and Red Hat.
Summary
The Linux kernel isofs filesystem uses buffer_heads, which do not handle block sizes larger than PAGE_SIZE. Mounting such a filesystem hits a BUG_ON in folio_set_bh on the first __bread_gfp call. Linux kernel versions from 2.6.12 are affected until the fixed releases listed in the solution.
Written with Claude Haiku 5.5 from the sources below · 2026-10-28
Description from the CNA
In the Linux kernel, the following vulnerability has been resolved: isofs: handle set_blocksize failures isofs uses buffer_heads, which don't handle block size > PAGE_SIZE well. Without this, mounting we will hit the BUG_ON(offset >= folio_size(folio)); in folio_set_bh on the first __bread_gfp call.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
Fixed Linux kernel releases are 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.111, 6.18.53 and 7.2. Red Hat lists Red Hat Enterprise Linux 10 as affected, with no fix available.
Written with Claude Haiku 5.5 from the sources below · 2026-10-28
- Fix · CNA Linux (Linux) Fixed in 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.111, 6.18.53, 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 |
Not affected: 5 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4
Timeline
- 2026-10-23 Threatist record created from CVE-2026-98879
- 2026-10-23 Alias added: GHSA-q9wc-mgjh-78f8
- 2026-10-26 Fix available: Linux/Linux@0 · CNA
- 2026-10-26 Affected versions changed · Red Hat
- 2026-10-26 CVSS score added · Red Hat
References
Other 7
- https://git.kernel.org/stable/c/6db7f0ba365786304558db6a3d52013ae176e03e
- https://git.kernel.org/stable/c/61f277bf35f533b602984f0e55900111fe52f31a
- https://git.kernel.org/stable/c/cebde6d88e34396c29f2f001d90e921677cc17d6
- https://git.kernel.org/stable/c/28d1f6aa14f5924e36602b7a31c9141d34de0b9c
- https://git.kernel.org/stable/c/9c97e3b1152d3092581745189f5d2f04c6404ef9
- https://git.kernel.org/stable/c/9584ab6283721e5aab485c79bd06c2f78d89e55c
- https://git.kernel.org/stable/c/25ef4c4d9f0e96fb89c0ae0d7127c3f12a31bc32
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Sources
- CVE-2026-98879 · CVE Program
- CVE-2026-98879 · NVD
- FIRST EPSS
- GHSA-q9wc-mgjh-78f8 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-98879 · 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