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CVE-2026-80810· NVD / CVE Program· CNA Linux

io_uring/rsrc: fix folio size overflow in io_vec_fill_bvec()

In the Linux kernel, the following vulnerability has been resolved: io_uring/rsrc: fix folio size overflow in io_vec_fill_bvec() io_vec_fill_bvec() computes the folio size with a plain int 1: unsigned long folio_size = 1 << imu->folio_shift; imu->folio_shift is unsigned int and comes from folio_shift() of the folio backing the registered buffer, so it can be 32 or more on a 64 bit kernel. Shifting int 1 that far is undefined, and on x86 and arm64 the count is taken modulo 32, so a shift of 34 yields 4 rather than 16G. Every other folio_shift shift in this file already uses 1UL. The result is that the segment estimate and the fill loop disagree. io_estimate_bvec_size() sizes the bvec array with the real shift: max_segs += (iov[i].iov_len >> shift) + 2; so a 1M iovec on a 16G folio is charged 2 segments, while io_vec_fill_bvec() then walks the same iovec in folio_size chunks of 4 bytes and writes res_bvec[bvec_idx] a quarter of a million times, past the end of the array it was given. src_bvec is advanced once per iteration as well, so imu->bvec is read past its end at the same time. validate_fixed_range() only checks that the range is inside the registered buffer and does not bound the segment count. Reaching it needs a folio with a shift of at least 32, which means a gigantic hugetlb page: 16G on arm64 with 64K pages, where CONT_PMD_SHIFT is 34 and hugetlb_add_hstate(CONT_PMD_SHIFT - PAGE_SHIFT) registers that size, and likewise on powerpc. x86_64 tops out at 1G, so a shift of 30, which still fits in int and is unaffected. Use 1UL, as the rest of the file does.

—No exploit Fix available
Published
Sep 4, 2026
Updated
Sep 4, 2026
EPSS
0.2% · 10th percentile
CWE
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CVSS
0 / 40 · —
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

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Affected systems

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Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 6.15affected
    • 9ef4cbbcb4ac3786a1a4164507511b76b2a572c5 and later · before 45c945107e007b1fb73e21cd220277652a45521aaffected · git
    • 9ef4cbbcb4ac3786a1a4164507511b76b2a572c5 and later · before 6b308c37fbeba3aa8c634fb1ed53e2f63a5d5a5caffected · git
    • 9ef4cbbcb4ac3786a1a4164507511b76b2a572c5 and later · before 3267d7c8ba51642117f7bdd1ece02b2540668476affected · git
    • 9ef4cbbcb4ac3786a1a4164507511b76b2a572c5 and later · before 3f3a6a16bbe8bde76532d9415438f8cdef439e5daffected · git
    • before 6.15not affected · semver
    • 6.18.47 and later · up to and including 6.18.*not affected · semver
    • 7.1.11 and later · up to and including 7.1.*not affected · semver
    • 7.2.1 and later · up to and including 7.2.*not affected · semver
    • 7.3-rc1 and laternot affected · original_commit_for_fix

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:14linuxbefore 7.1.12-17.1.12-1

Same product

linux: all records

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Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux3267d7c8ba51642117f7bdd1ece02b2540668476Vendor (CNA)
Linux Linux3f3a6a16bbe8bde76532d9415438f8cdef439e5dVendor (CNA)
Linux Linux45c945107e007b1fb73e21cd220277652a45521aVendor (CNA)
Linux Linux6b308c37fbeba3aa8c634fb1ed53e2f63a5d5a5cVendor (CNA)
debian:linux7.1.12-1 · Debian:14Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

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EPSS, last 120 days

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Patch and commit links

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Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

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No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

No CVSS vector for this record, so attack conditions can't be derived.

Weakness class (CWE)

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Attack context

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Change log

  1. Fix✗ → ✓

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References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

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