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CVE-2026-46149 Linux CVE debrief

A buffer over-read vulnerability exists in the Linux kernel's SCSI target subsystem. The function `tg_pt_gp_members_show()` in `drivers/target/target_core_configfs.c` uses `snprintf()` to format LUN paths into a 256-byte stack buffer, then copies the result using `memcpy()` based on `snprintf()`'s return value. Because `snprintf()` returns the length the output *would* have had (not the truncated length), and iSCSI IQN names can reach 223 bytes, the return value can exceed the buffer size. The existing check only validates the destination page write, not the source read, causing `memcpy()` to read past the stack buffer boundary. When `CONFIG_FORTIFY_SOURCE` is enabled, this triggers `fortify_panic()`. This vulnerability is the `tg_pt_gp_members_show()` variant of a similar issue previously fixed in `target_lu_gp_members_show()` via commit 27e06650a5ea.

Vendor
Linux
Product
Unknown
CVSS
HIGH 7.1
CISA KEV
Not listed in stored evidence
Original CVE published
2026-05-28
Original CVE updated
2026-06-10
Advisory published
2026-05-28
Advisory updated
2026-06-10

Who should care

System administrators running Linux kernels with iSCSI target mode (LIO/target_core_mod) enabled; security teams monitoring for kernel memory safety issues; organizations with `CONFIG_FORTIFY_SOURCE` enabled experiencing unexpected `fortify_panic()` events.

Technical summary

The vulnerability stems from incorrect handling of `snprintf()` return values in `tg_pt_gp_members_show()`. When formatting LUN paths with long iSCSI IQN names (up to 223 bytes), the unconstrained return value causes `memcpy()` to read beyond the 256-byte stack buffer. The fix bounds the return value to `sizeof(buf) - 1`, matching the pattern applied to `target_lu_gp_members_show()` in commit 27e06650a5ea.

Defensive priority

medium

Recommended defensive actions

  • Apply the relevant stable kernel patch for your branch: 6.14 (ref-4), 6.12 (ref-5), 6.6 (ref-6), 6.1 (ref-7), or 5.15 (ref-8)
  • Rebuild kernel with the applied patch and reboot systems serving iSCSI targets
  • Verify CONFIG_FORTIFY_SOURCE is enabled to detect similar memory safety issues
  • Audit custom SCSI target configurations with long fabric WWN names for potential exposure
  • Monitor kernel logs for fortify_panic() messages indicating exploitation attempts

Evidence notes

The CVE description and kernel commit references confirm the vulnerability is a stack buffer over-read in SCSI target configfs handling, specifically in `tg_pt_gp_members_show()`. The fix applies the same pattern used in commit 27e06650a5ea for `target_lu_gp_members_show()`. Multiple stable kernel branches received backports.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-46149 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-46149

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-46149 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-46149

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/00d91bfdce5033f5d9b4915638ae9b0553848b5d

    416baaa9-dc9f-4396-8d5f-8c081fb06d67

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/1f678d13e939f91840cb1ebe9b88544923539d3c

    416baaa9-dc9f-4396-8d5f-8c081fb06d67

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/72cc5ea7ef32bb5fa38bf0dd2e56fcd73aa8c89e

    416baaa9-dc9f-4396-8d5f-8c081fb06d67

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/772a896a56e0e3ef9424a025cec9176f9d8f4552

    416baaa9-dc9f-4396-8d5f-8c081fb06d67

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/e501154f9d82c95d2719bcbbaf679d8fd3226ef7

    416baaa9-dc9f-4396-8d5f-8c081fb06d67

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.