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CVE Record

CVE-2023-53630: iommufd: Fix unpinning of pages when an access is present

In the Linux kernel, the following vulnerability has been resolved: iommufd: Fix unpinning of pages when an access is present syzkaller found that the calculation of batch_last_index should use 'start_index' since at input to this function the batch is either empty or it has already been adjusted to cross any accesses so it will start at the point we are unmapping from. Getting this wrong causes the unmap to run over the end of the pages which corrupts pages that were never mapped. In most cases this triggers the num pinned debugging: WARNING: CPU: 0 PID: 557 at drivers/iommu/iommufd/pages.c:294 __iopt_area_unfill_domain+0x152/0x560 Modules linked in: CPU: 0 PID: 557 Comm: repro Not tainted 6.3.0-rc2-eeac8ede1755 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014 RIP: 0010:__iopt_area_unfill_domain+0x152/0x560 Code: d2 0f ff 44 8b 64 24 54 48 8b 44 24 48 31 ff 44 89 e6 48 89 44 24 38 e8 fc d3 0f ff 45 85 e4 0f 85 eb 01 00 00 e8 0e d2 0f ff <0f> 0b e8 07 d2 0f ff 48 8b 44 24 38 89 5c 24 58 89 18 8b 44 24 54 RSP: 0018:ffffc9000108baf0 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 00000000ffffffff RCX: ffffffff821e3f85 RDX: 0000000000000000 RSI: ffff88800faf0000 RDI: 0000000000000002 RBP: ffffc9000108bd18 R08: 000000000003ca25 R09: 0000000000000014 R10: 000000000003ca00 R11: 0000000000000024 R12: 0000000000000004 R13: 0000000000000801 R14: 00000000000007ff R15: 0000000000000800 FS: 00007f3499ce1740(0000) GS:ffff88807dc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020000243 CR3: 00000000179c2001 CR4: 0000000000770ef0 PKRU: 55555554 Call Trace: <TASK> iopt_area_unfill_domain+0x32/0x40 iopt_table_remove_domain+0x23f/0x4c0 iommufd_device_selftest_detach+0x3a/0x90 iommufd_selftest_destroy+0x55/0x70 iommufd_object_destroy_user+0xce/0x130 iommufd_destroy+0xa2/0xc0 iommufd_fops_ioctl+0x206/0x330 __x64_sys_ioctl+0x10e/0x160 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x72/0xdc Also add some useful WARN_ON sanity checks.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

This is a Linux kernel memory-management flaw in iommufd. A bad page-unpinning calculation can corrupt pages that were not part of the mapping. The public record shows it was found by syzkaller and fixed in stable kernel commits, but does not provide a CVSS score or evidence of active exploitation.

Executive priority

Schedule remediation through the kernel patch process, with higher urgency for systems hosting untrusted local workloads or virtualization-related workloads. Current public evidence does not support emergency exploitation response, but kernel memory corruption should not remain untracked.

Technical view

In iommufd page unmap handling, batch_last_index was calculated from the wrong index. When an access is present, unmap processing can run past the intended page range and corrupt unrelated pages. The source describes kernel WARN_ON debugging output and adds sanity checks alongside the fix.

Likely exposure

Exposure appears limited to Linux systems running affected kernel builds with iommufd code paths available or exercised. The bundle names Linux 6.2-era versions and stable fix commits, but does not fully define distribution package impact or backport status.

Exploitation context

The source cites syzkaller discovery and a reproducer-like kernel warning trace in QEMU. It does not cite public exploitation, weaponized exploit availability, or CISA KEV listing. Treat exploitation status as unconfirmed.

Researcher notes

Evidence is incomplete for real-world exploitability, privileges required, and distribution-specific exposure. The most concrete artifacts are the Linux kernel description, syzkaller-triggered warning trace, affected version metadata, and two stable commit references.

Mitigation direction

  • Upgrade to a vendor kernel containing the referenced stable fixes.
  • Check distribution advisories for backported fixes before relying on version numbers alone.
  • Prioritize shared, virtualized, or untrusted-workload Linux systems for review.
  • Follow vendor guidance if immediate kernel upgrade is not available.

Validation and detection

  • Inventory Linux kernel versions across affected fleets.
  • Confirm whether vendor kernel packages include the referenced stable commits.
  • Review kernel changelogs or advisory notes for CVE-2023-53630.
  • Check whether iommufd-related functionality is present on exposed systems.
Prepared
Confidence
medium
Sources
4

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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CVE-2023-53630 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
0ADP providers
3Source links

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

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Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux8d160cd4d5066f864ec0f2c981470e55ac03ac27, 8d160cd4d5066f864ec0f2c981470e55ac03ac27unaffected
LinuxLinux6.2, 0, 6.2.11, 6.3affected
Weakness

CWE details

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