CVE-2026-89775— KVM: arm64: Handle negative S1 walk levels in VNCR TLB size evaluation
Quick assessment
Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.
In the Linux kernel, the following vulnerability has been resolved: KVM: arm64: Handle negative S1 walk levels in VNCR TLB size evaluation Computing the effects of a TLB invalidation involves looking at the size of the mapping cached by the TLB. For S1 mapping
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I. Basic Information for CVE-2026-89775
Vulnerability Information
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Vulnerability Title
KVM: arm64: Handle negative S1 walk levels in VNCR TLB size evaluation
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved:
KVM: arm64: Handle negative S1 walk levels in VNCR TLB size evaluation
Computing the effects of a TLB invalidation involves looking at
the size of the mapping cached by the TLB. For S1 mappings such as
VNCR, this is deducted from the combination of the base granule size
and the mapping level.
However, this implies that the S1 MMU is *on*. When the MMU is off,
we indicate this with the level being set to a "creative" value of
-127 (S1_MMU_DISABLED).
This ends-up being misinterpreted by pgshift_level_to_ttl() as it
doesn't handle negative levels at all (the level is immediately cast
to a u8 and only the bottom two bits considered), leading to an
invalidation size of 0. Not helpful.
Tidy-up pgshift_level_to_ttl() to handle these negative levels, and
ttl_to_size() to always return SZ_1G when no valid TTL is present.
This allows the removal of open-coded checks for similar situations.
Note that the check for a negative value not explicitely checking for
S1_MMU_DISABLED is deliberate, so that actual negative levels introduced
with LVA2 and D128 can take the same path if we ever support them.
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Affected Products
II. Public POCs for CVE-2026-89775
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Other References for CVE-2026-89775 (3)
Same Patch Batch · Linux · 2026-09-16 · 276 CVEs total
| CVE-2026-89860 | scsi: qla2xxx: Initialize NVMe abort_work once at submission | |
| CVE-2026-89877 | media: saa7164: fix cleanup on resource allocation failure | |
| CVE-2026-89875 | media: ti: vpe: quiesce overflow recovery before freeing streams | |
| CVE-2026-89876 | media: tda18250: fix possible integer overflow | |
| CVE-2026-89874 | media: v4l2-async: avoid deleting unlinked ASC entry on link error | |
| CVE-2026-89872 | media: v4l2-fwnode: Fix fwnode leak in v4l2_fwnode_parse_link | |
| CVE-2026-89873 | media: v4l2-ctrls: validate HEVC EXT SPS RPS counts | |
| CVE-2026-89871 | media: video-i2c: fix kthread error pointer left in kthread_vid_cap on failure | |
| CVE-2026-89870 | media: zoran: Avoid freeing a registered video_device twice | |
| CVE-2026-89869 | media: qcom: iris: use disable_irq() during power-off | |
| CVE-2026-89868 | media: chips-media: wave5: Add timeout while stop_streaming | |
| CVE-2026-89867 | media: chips-media: wave5: Defer job_finish() only when a DEC_PIC was queued | |
| CVE-2026-89866 | media: chips-media: wave5: Resume device before setting EOS flag | |
| CVE-2026-89865 | scsi: qla2xxx: Zero SFP DMA buffer in FRU/I2C bsg handlers | |
| CVE-2026-89864 | scsi: qla2xxx: Bound i2c->length in I2C bsg handlers | |
| CVE-2026-89863 | scsi: qla2xxx: edif: Fix NULL pointer deref in RX SA delete check | |
| CVE-2026-89862 | scsi: qla2xxx: Fix BSG job leak on validate flash image error path | |
| CVE-2026-89861 | scsi: qla2xxx: Hold vport reference in qla24xx_report_id_acquisition() | |
| CVE-2026-89850 | scsi: qla2xxx: Don't query firmware state while chip is down | |
| CVE-2026-89848 | scsi: qla2xxx: Quiesce response IRQ before freeing request queue |
Showing top 20 of 276 CVEs. View all on vendor page → →
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Same vendor: Linux
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CVE-2026-90049
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CVE-2026-90048
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V. Comments for CVE-2026-89775
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