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TI-2026-13338 Aliases CVE-2026-15923

Infinite loop denial of service in Zephyr SDIO byte-I/O from a card-supplied zero max_blk_size

Priority LOW 21CWE-835Published · Updated

Key facts

Attack vector
Physical
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-835.

Summary

The Zephyr SDIO subsystem function sdio_io_rw_extended_helper() in subsys/sd/sdio.c finishes transfers with a byte-I/O loop that uses size = MIN(remaining, func->cis.max_blk_size) as the per-iteration step. The value func->cis.max_blk_size is decoded directly from the SDIO card's CIS FUNCE tuple in sdio_decode_cis() and is not validated. When a card reports a maximum block size of zero, size is always 0, remaining never decreases, and the loop spins forever. The loop is reached from the public SDIO client API used by drivers, including sdio_read_fifo(), sdio_write_fifo(), and the incrementing register read/write helpers, each of which enters the loop while holding the per-card mutex func->card->lock. A card advertising max_blk_size == 0 therefore hangs the calling thread permanently on its first non-block-aligned transfer and never releases the mutex, denying service to the SDIO peripheral (and any subsystem such as Wi-Fi that depends on it) until the device is reset. The malicious value must come from the SDIO card itself, so the defect is exploitable where a removable SDIO/combo card slot lets an attacker insert a crafted or malfunctioning card (a physical attack vector); on boards with a soldered SDIO peripheral it is not attacker-influenceable. There is no memory-safety, confidentiality, or integrity impact — only a permanent availability loss. The fix returns -EIO when func->cis.max_blk_size is zero, before the loop is entered.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.0023 13th percentileScored 2026-11-07
Fix Fixed zephyr (zephyrproject): 4.3.2, 4.4.2

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
zephyrprojectzephyr3.6.0 to before 4.3.2; 4.4.0 to before 4.4.24.3.2, 4.4.2Patch availableCNA
  • zephyr Vendorzephyrproject Affected 3.6.0 to before 4.3.2; 4.4.0 to before 4.4.2 Fixed in 4.3.2, 4.4.2 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:o:zephyrproject:zephyr:*:*:*:*:*:*:*:*——zephyrproject
  • cpe:2.3:o:zephyrproject:zephyr:*:*:*:*:*:*:*:* Versions — — ·zephyrproject

Remediation

  • Fix · CNA zephyr (zephyrproject) Fixed in 4.3.2, 4.4.2

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    zephyrproject zephyr 4.3.2, 4.4.2

    3 records Highest priority Priority LOW 3 LOW

    Other records, highest priority first

    • TI-2026-13318 Zephyr IPv6 Neighbor Discovery zero reachable time from crafted Router Advertisement causes assertion/DoSPriority LOW 29
    • TI-2026-13514 Kernel panic in the it82xx2 USB device controller driver via re-initialization of a busy delayable work itemPriority LOW 21
    Show all 3 records →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-15923
  2. 2026-11-04 Fix available: [email protected] · CNA

References

Patch 1

Other 1

  • TI-2026-04422 Out-of-bounds read/write in HTTP WebSocket upgrade via non-null-terminated Sec-WebSocket-Key CVSS 3.1CRITICAL 9.8
  • TI-2026-01361 dns: memory‑safety issue in the DNS name parser CVSS 3.1CRITICAL 9.8
  • TI-2026-09174 Unterminated URI buffer causes out-of-bounds read in LwM2M firmware pull (Package URI) CVSS 3.1CRITICAL 9.1
  • TI-2026-09168 Stack buffer overflow in `net_ipaddr_parse()` IPv4 address-with-port parsing in `subsys/net/ip/utils.c` CVSS 3.1CRITICAL 9.8
  • TI-2024-09625 net: lib: http_server: Buffer Under-read CVSS 3.1HIGH 8.6
  • TI-2021-02863 Usb bluetooth device ACL read cb buffer overflow CVSS 3.1CRITICAL 9.6
See all 341 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences